Don't worry about her parents not liking you, just do what you can. There's a lot of people who don't have a good relationship with their in-laws for the most petty reasons. The question is, what is your partner saying about all this? If she's siding with her parents, that's a bad sign.
A Muslim who is not practicing can very easily fully turn to Islam. I've noticed it usually takes something like a loss, seeing imaginary signs from God, etc. You need to consider this so you don't end up in a situation where you break up, or she tries to pressure you to convert. I rarely ever see Muslims who don't practice their whole lives. They almost always turn back to the faith, one way or another.