you are doing the right things it seems and it is to be expected that your wife will have BIG ups and downs over the next period of time...i am really happy to see your second post!!
If you keep doing what you are doing and hang in there, its a good chance you will stay amicable at worst and stay close and friendly...
also take the lawyer stuff seriously. YOu have no idea what the lawyer is telling her, you have no idea what your wife's lawyer is capable of..i found this out the hard way..in the end my wife's good nature won out and she didn't do all the awful things suggested by her lawyer(just some of them..hehe), so you do need to lawyer up even if its distasteful
Is there mediation in your province?? We mediated custody and it was actually a lifesaver and we ended up literally writing out our custody arrangement on a piece of paper and left only the money and property to the lawyers... it saved alot of money and let us survive the terrible process of "how to deal with the kids"
I wish you the best with your mom... my mom fell ill around the time i transitioned as well and it became a very sad time for my extended family so i know what its like
....you have to hang in there for all of them and for yourself and i've said many times the best thing you can do for everybody is to thrive and be productive..