Am I sinful for what my wife is forced into by her family, regarding removing her hijab and wearing makeup? And am I obligated to divorce her?

It is not permissible for the girl's father to force her to remove her hijab or to display her adornments. He must be advised, and those who have influence over him should be urged to stop his disobedience. Efforts should be made to remove the wife from this corrupt environment by providing an independent home, enabling her to wear the شرعي (Shar'i) hijab. As long as circumstances do not allow for independence, you should advise the girl about the obligation of hijab and that obedience to Allah takes precedence over obedience to her father, while also advising the father wisely. There is no sin upon you if you do what you can, and it is not advisable to divorce her as long as she is not content with what she is doing.