Final graduation thesis - Team members won't cooperate anymore
Other team members may have been put off by your ambition to make the project publishable, rather than merely sufficient for graduation. They only signed up for a graduation thesis project, not an academic paper.

To meet their needs and try to get them back on board, I suggest splitting your planning into two phases, with two different objectives:


Graduation Thesis This should be a team project, but should only include work that is necessary for graduation. Do everything you can to limit the scope and difficulty, so that all members of the team can understand the project and contribute with a reasonable effort. You will then be in a strong position when asking the rest of the team to contribute.
Publication This is your personal project, not shared by the rest of the team. You should expect to do all the additional work for it after completion of the graduation thesis sub-project. It may involve rewriting material to give a more sophisticated treatment, as well as more research than is necessary for graduation.