I think I too would start looking for my own apartment. He is not going to be too great if after rehab he comes straight back to his home instead of going to a Sober Living House for at least another 90 days or so and I am not sure I would want him around my child.
He will be bouncing off the walls for some time so looking for an apartment would be a good idea, but it is your call.
I do like the note you are going to give her with ALL of the child's possessions, good for you!!!!
Sounds like you have some really good boundaries going!
Love and hugs,