I really agree with the Snowbird entry - her age is always going to be difficult to pin down and not very relevant, given who she is.
Since Shaman spent 10 years in solitude, and was a renowned physician prior to that, 45 years is a pretty good age for the good doctor.
While "Mac" may be younger than Shaman (and Heather definitely is), I would think that Mac is pushing 40 more than 30 [entertaining the "time in space"/cyborg stuff doesn't help IMO]; if Heather was 28 in vol. 1 # 13 - 14, and 7 years have elapsed from vol. 1 and vol. 4, I would think Heather is 35, at the most.
The twins should be youngest of original group; Walter around the same age as Mac (40ish).
I don't have a clue about Judd.
Drafting children/teenagers to be part of Dept. H is something a responsible party should take a look at.