I have several XR2 transmissions but no automatics, sorry. There are many people looking for them, the differential eating through the case seems to be a very very common problem with them.
I'm not sure on the interchangeability, but you might be able to source an F4-EAT from a earlier Mercury Tracer (89?)
I know the Festiva automatic will bolt to the engine as well, but it's not electronically controlled. These seem to have proven to be more reliable. Not sure what is involved with converting to one
Good luck
-Matt