As explained in the license page, the licenses under which all the models are distributed in the free models page let you use them for commercial purpose and I check it's the case for each one.
Crediting their author is a requirement, but when you mix many different models in a same project, I don't know which convenient option would be admitted (I don't speak here of the redistribution of 3D models individually or in libraries):
- building a list containing all the authors cited in the free models page and add it to documents presenting the project even if you don't use all of them,
- adding a mention with an URL to the free models page in documents presenting the project,
- listing only the authors of the models used in the project.

What do you think okh?