I think he's great. There's a lot to like here. I love using him on Scientist teams.

Does his special Trait work with the Wall Constructs? (This character can use Barrier as a free action, but only to place 2 squares of blocking terrain) So would it allow him to power action barrier (enemy takes a d6 of penetrating damage), then free action Barrier around the same enemy. (then roll another d6 and they take that much again)

This does not work with any outside instance if Barrier.... It says when he uses "it", meaning the Barrier from his trait.... For it to work with equipment or constructs, it would need to be worded like this, "when Mr. Spock uses Barrier, do x, y, and z."