I couldn’t come up with a better title so let’s just forget about it. I just wanted to know if Kara’s BBS affected the walls. That’s all.
If it is a summonable minion, Kara’s BBS will affect it. If it is a spell, then any tokens summoned by the spell won’t be affected.
Source: Played Kara for the last three days of the season, felt bad for everyone I played against.
That being said, in theory you could have a wall Hailstoned back into your hand, and then trigger the BBS, which would affect the wall.