Joanne Kelly (Myka on Warehouse 13), Christopher Heyerdahl (SG:A, Sanctuary, and Hell on Wheels), Michael Shanks (Daniel on SG-1), and the last one....I'm not sure, but it looks like Tori Higginson (Weir, on SG:A); it's been awhile since I've seen her.
I don't don't watch Warehouse 13.
Christopher Heyerdahl was in wraith makeup.
Tori's face has filled out a bit (tho' she still looks great).
I would never have guessed that was Michael Shanks.
And I will always recognize that hunk on the right.