Straight up just gonna say I’m not very experienced with blender, but I’m interested in trying to edit video game character models from the models resource and such into bbws for modding purposes, so does anyone know the best way to do this? Or if it even is possible without just modelling a belly and sticking it on?
It is entirely possible, but requires practice to do that (at least in my limited experience with Blender myself and from one of my friends who does mods). Consider that not all models are equally and some have more or less polygons to work with and depends on what you want to achieve. Also, think that making the model too big may make it not look good in motion if you want to use in a game or have a lot of clipping issues.
If you are using Blender as you say, try to learn some tips on modelling and scultping (such as using mask, mirror the scultps, etc). That is from my short time on it, hopefully someone more experienced can provide you with more helpful tips.
Different games have different engines. First you need to find if there is tools which let you edit models for specific game, because I don’t think you are skilled enough to create modding tools by yourself. Find tools for modding → learn how this tools work → extract model from game archive → import model into 3d modelling software → edit model and prepare it for export by learning of every option which should be corrected to make this model work correctly in this particular game → export model and import it back in game archive by using modding tool. I don’t know any game for which there is a lot of tools for modding, so I guess there is no “best way to do this”, because there is only one way to do this.