27.5 vs 29 for short rider

[cmbicycles]

My kids are outgrowing their 14" 26er hardtails so I'm starting to look for something bigger. Both are about 5'2 at the moment, I'm 6'5 so likely they are doomed.
At current height would a 29er be an awkward fit with the small frame onto bigger wheels, or is 27.5/650b a better wheel size at this stage. They mostly ride single track and considering trying a race at some point, but nothing too serious besides getting out and enjoying riding... I'm the gear junkie planning the upgrades
I am also considering moving to a 29er for myself, so also thinking about "standardized" wheel size for bikes in the house. Currently we all have 26" mtn bikes while we tried the mtn bike team experiment to see if we enjoyed it... that seems to have been a success.

Seems like 29er is more popular around here for the trails we ride in central VA.