IMO, the first one is too 'centered'. Composition doesn't really work for me. Also, their names are difficult to read. Logo is fine, like it!
2nd one is stiff and she is supporting him a little too much. Perhaps it's just me, but I feel like the woman should be 'glorified', so to speak and the guy should be the 'supporter'. Switch them and this pose works much better, imo.
3rd one is also really centered and they don't seem that engaged to me. If they were touching noses or something like that, it feels like it'd be stronger.
4th one is sort of the same way... they need to be engaged with each other. Drape her arm over his shoulder. It looks stiff and unemotional this way...
5th also very centered. Try using the rule of thirds. Nice image, though. 