The issue with someone porting into your area from someplace else is that they almost never have income when they move. 

Should I move the house to an LLC?

Your leverage is with the seller.Get him to move out, making it a viable 2-family. 

Also fix and flips are a timing thing and you would usually be moving fast, conventional could possibly slow the process

The best is when they move in and immediately begin making maintenance demands for things they broke themselves, or because some man they lied about not being on the lease is living there and broke it, or one of their endless supply of children broke it  and it's like you still owe like a grand from your deposit maybe don't take such a tone when you fuss over maintenance issues you created in the first place - but God forbid you withhold whatever pithy deposit they did manage to cough up for damages because they go full throttle Jerry Springer guest in 2.2 seconds. 

We've moved on to Blue Ridge in our search as the numbers make more sense.

There mother called us just over a month ago and informed us that they were being evicted and if they can’t find somewhere that she can afford, they will have to move back with family, away from GA.

2) If they decide to take the offer and move out in April, does that override the 90 day notice needed (see below)?

Back when they moved in, we did a walkthrough/checklist, we all signed it, and I kept the original paperwork, but never sent them a copy.

I would wait till after you have your first deal before helping your mother move into real estate.