A lot of people think that the 'Neolithic revolution' happened in more-or-less a single bound: sedentism, farming, pastoralism, ground-stone celts, pottery, and so on, all happening together, or causing one another. In many causes, these traits do co-occur. The domestication of animals in the Near East coincided almost exactly with the domestication of grains, and while the domesticating communities didn't use pottery, they did use ground-stone tools and other Neolithic-y traits.
But in fact, there are plenty of different logical combinations of these traits that have been found in the archaeological and ethnographic records. There have been plenty of societies, for instance, that were sedentary but not agricultural. I can think of at least three - Khok Phanom Di in Thailand, the Ertebølle cultures of late-sixth to fourth millennium BCE Scandinavia, and Lepenski Vir, a site in Serbia, situated along the Iron Gates (a ravine through which the Danube flows). There were doubtless many more, especially in the Americas (the entire northwest coast was like this, and California too, but I haven't read about these things in enough detail recently to use them as good examples).
The relevant variable here is the productivity of the land around the settlement; if the area is especially fecund, then there is no pressure to domesticate plants and spend time sowing them, unless there are other constraints. Khok Phanom Di, a site excavated by Charles Higham and Rachanie Thosarat, was situated in an area of tropical forest so productive that the graves of Khok Phanom Di's residents show a high level of stratification. The site was permanently occupied because there was an abundance of food available, and there appears to have been some serious differentiation between the most and least powerful members of society. Agriculture is evidently not necessary for social inequality.
Likewise the Ertebølle sites, which were permanently occupied and in contact with agricultural peoples (IIRC, the Linearbandkeramik [LBK] societies of the loess plains of central and western Europe). Ertebølle life was so richly provisioned that despite awareness of agriculture, the people consciously avoided it (although they did trade for agricultural products from the LBK people, it seems). When agriculture did spread to formerly Ertebølle areas, it did so exceptionally quickly, spreading over an area of 500km in around a century. The ground was prepared for agriculture because the locals were 'delayed-return' foragers, meaning that, in common with farmers, they stored a lot of food and invested time in preparing their food products. This contrasts with 'immediate-return' societies, who do not invest as much time in preparing and storing food - Khok Phanom Di was occupied by people with an immediate-return economy. Immediate-return foragers are what is generally meant by the term 'hunter-gatherer'.
There has been a tendency to believe that such sedentary foragers must have been peaceful. It is reasonably common to suggest, for example, that the supposedly peaceful nature of pre-Columbian Californian life was a direct result of the fecundity of the region and the ease of living in mild, productive, Mediterranean climate. Unfortunately, this isn't actually the case. While instances of violence are found in all human communities, they are especially common in sedentary tribal societies, no matter the economy, and many people at Lepenski Vir (and lots of other Mesolithic sites - see the link to see just how arbitrary the classification of these sites is) appear to have died from inter-communal violence. People always have more to fight about than merely food and provisioning, and satisfying basic requirements doesn't necessarily lead to a fall in belligerence.
So you can have sedentary foragers, and these sedentary foragers can certainly make pottery and build permanent dwellings, and exhibit high degrees of social stratification. You can also have transhumant ('nomadic') communities that grow crops. While this is comparatively rare, it is possible to sow crops, leave in search of other food sources (or in search of trade, etc), and return when they are ready for harvest. This is only possible in some areas and is, of course, a risky strategy, but there are examples of communities that managed to mix majority sedentism with a little bit of seasonal population movement. Many groups on the Eurasian steppes grew small quantities of grain in addition to rearing animals, and larger portions of the community were transhumant.
In fact, it is possible for the basis of a pre-industrial economy to be:
- foraging, mostly sedentary, but with some seasonal movements among some segments of the population (hunters in search of game);
- sedentary and pastoral (animals in kraals providing most of the products, alongside foraging for plant foods);
- transhumant and pastoral (animals herded on horseback, alongside foraging);
- transhumant and pastoral (animals herded without horses or camels, alongside foraging);
- transhumant and pastoral with some horticulture;
- entirely sedentary, but foraging, with an immediate-return economy;
- entirely sedentary, but foraging, with a delayed-return economy;
- agricultural and pastoral, but not fully sedentary;
- sedentary, agricultural, and pastoral, with foraging;
- sedentary, agricultural, and pastoral;
I'm sure there are more variations to this list. And it is certainly possible to use ground-stone celts and pottery at any point, and, indeed, it is possible for social stratification and inequality to occur in almost any type of economy (what the power-hungry aspiring leaders need is leverage, and that can come from many sources, not merely control over an agricultural surplus; it is, though, less common for transhumant foragers to have more complex social structures, as prospective leaders have little or no leverage, and there is often an egalitarian ethos to such communities). The reason that these traits tend to go together, but don't inevitably do so, is fairly simple.
If you have a foraging society that regularly moves locations in search of better food sources, then when you come across a location that provides exceptionally well for your community, you are likely to settle down, because seasonal movement can be risky. If the principal resource you rely on is a resource that can easily be stored and processed with little effort and a lot of obvious benefits, then you are likely to develop a delayed-return foraging economy. If you have a sedentary society with a delayed-return foraging economy, then you are more likely to need pottery to store and cook food products, so the invention is that much more likely.
You may need ground-stone tools to clear land for large villagers and to work on communal projects, so that invention is much more likely, too. You are much more likely to domesticate plants, given that you've got experience with such things as a result of manipulating your existing food sources, despite relying on foraging. You are then likely to domesticate local animals, because game sources will be reduced in the area around the village, and because it is easier to provision animals with agricultural products than with wild foods. This can lead to a larger population, pressure on resources, and the development of greater social stratification as a result of the need to allocate resources and arbitrate in disputes, and as a result of the greater concentration of wealth in certain hands (due to the storing of food, etc). Societies with these traits will often end up dominating any societies who do not possess them. Foragers are likely to be out-competed by the larger populations and more sophisticated technologies and social structures of their agricultural/pastoral/delayed-return neighbours.
It is for reasons like this that sedentism, the domestication of plants and animals, and the use of pottery and ground-stone tools (the 'Neolithic package') go together and spread together. But none of this is inevitable. It is possible to have any number of other economies and any number of other traits, and it is notable that the earliest agricultural/pastoral sites in the world, in the early Holocene Fertile Crescent, were pre-ceramic, despite possessing all the other Neolithic traits.
The development of a more complex economy is clearly not a unilineal process, of course. It depends on a lot of different changes occurring and causing one another. It is also important to remember that it is people making decisions that causes such things; that many of these decisions are unconscious is irrelevant to the fact that the direct causes of human actions are mental. Since this is so, if people decide not to do something, then they won't do it (this is, as you can tell, a tautology [hence the problem of akrasia]). The Ertebølle people consciously avoided taking up agriculture despite being aware of it for a long time. They perceived the advantages of an agricultural economy to be outweighed by the disadvantages, for whatever reason, and continued to pursue a delayed-return foraging economy.
So, while the process isn't unilineal, and is dependent on mental causes (what tends to be called 'agency' by many historians and anthropologists, who see it as a way of circumventing causation), it is also possible to generalise about the development and spread of Neolithic traits, and even the 'Neolithic package'.