As for the size ,it sounds like he could end up being in the 4-5 lb range.
As for her size .To me she is borderline "too small" I have seen many breed a 4 1/2 lb dam but I have onlyseen that with breeders that have been breeding for several years now. My dog was 6 lbs and I thought that was big enough and she still seemed so small since her body is so compact. I know you may not be asking about her size and what people think about that. I'm not trying to be rude in anyway so please don't take it like that. If she's had at least one litter then you could have some kind of idea but every whelp is different and you never know until she gives birth.
Keep in touch with a breeder/mentor and good luck with your furbabies
Genie
Cookie
Lola
Angel
Lucky