Oh my goodness what a real winner your MIL is....Unreal
She must be a miserable person to do you like this. I say family is family and there should not be one prefered over the other in any circumstance.
I am sure Renotta ( the breeder )will work something out with you as she is a really nice person and she does have understanding.
If I were you I would have no more to do with the MIL..That would serve her right and hey I would move to be with your family if I were you as they sound like they care.
Good Luck and keep us posted.

Go get your fur baby....