You were wondering why Bristleback was being considered a support after laning it as a support, it wasn't particularly apparent that you were aware of your poor lane setups.
My advice about not playing single draft is genuine, you can find out good lane combinations beforehand and it makes you far more appreciative of the role each member in the lane has to play if you are able to play an effective duo. As for "it helps us try out new heroes" I really don't understand the logic, it's the most restrictive draft of the lot. Just go all pick and work your way through them. I learned with a friend and we just laned together, for the first few games he carried I supported, then we switched. It takes long enough to learn how all the heroes can combo together without making it hard for yourself by choosing (or risking it with single draft) heroes that have absolutely no synergy.