Hi, there. I am in limbo, too, and a mom of 2 young kids. I've been in this limbo for 6 years, but I do have lesions and all mimics have been ruled out. It's a scary place to be, I know. If I have something that will benefit from treatment, I want to be able to move ahead and treat it!
Your symptoms to me don't sound 100% like MS, and your normal MRIs should put you at ease, but I also know what you mean by symptoms haunting you and that any unexplained symptoms can make you worry so much it's almost impossible to go on without pursuing a diagnosis, whether it be MS or not. I am just not one who can easily play the wait-and-see game. So, I personally keep pushing for more tests. But then again, I know I have lesions, so I know there's got to be something going on.
If you've had any vision problems, a VEP is a really easy test and could help put your mind more at ease. I would definitely get the bloodwork done to rule out any and all mimics like Lupus. The LP is not the most fun test, so I would wait on that one, because a negative LP doesn't rule MS out and is more likely to be negative in the early stages of MS anyhow. But if it would help put your mind at ease, you could always pursue it?
I hope you can find the answers that you are looking for soon. This community is a great place to educate yourself and to find support from other people who have been through the same thing.
I'm no expert but it sounds more like RA to me, especially the pain in your hip that gets better with movement and the elevated ANA. I think it's good that you're going to a rhuematologist. See what he/she has to say and then go from there. You can always go back to a neuro if the rheum. doesn't think there's anything going on in that field.
Good luck and let us know what you find out! There are many of us in limbo here and it's always helpful to share experiences!