Hi, 
 I love the end as it is. Normally, I'm not a fan of 'twist' endings, ones that (I find) cheat the reader of everything that has been developed up to this point. I like it, though, mostly because nothing happens next. Is it supernatural? Is it his imagination? A wrong IM (i.e., the wrong Jay)? I don't know, but I'd rather keep it that way. Perhaps the most important thing is that there is now communication. 

As for the family history, I rather like it the way it is. The cups are tied to a rather specific and compelling story, so that's a definite keeper. One of the difficulties I had before was that the other family histories lacked that kind of specificity: there were (if I may) a kind of generalized sense of working class background and the usual Irish/Polish touchstones (church, knitting, etc.). So, if the family history can be made that individual, then, yes, integrate them; otherwise, I'd recommend leaving it out. 

Hope this helps! Let me know if I left anything out.