I had the 200+ in freebuild. I've just tried some Kingmaker, the Volcano and Australia maps, and in both cases I too was only able to have 104 peasants. Once that limit was reached no more hovels could be built.I really don't know at this point if its an inbuilt limit for all Kingmaker maps, or something that can be set in the editor or a bug. I guess we may have to wait for some clarification from FireFly.In most skirmish maps I would be unlikely to have more peasants than that anyway as I'm generally building units and only have the minimum economy needed to support them and get some gold in, but it will be annoying if its something that can't be changed in other Kingmaker maps.
These are the different ways to increase your population and popularity in Stronghold Crusader 2. If you have any question pertaining to this guide, feel free to ask in the comments below! For The Stronghold Collection on the PC, GameFAQs has 23 cheat codes and secrets.