Played and saw wizards often in the weekly last night. Riding a boss is actually a really bad idea as the bosses don't even try to take cover and the plant players are getting very good at taking you off host's heads. I tried riding a couple last night and gave up as I would get almost instantly shot off since the boss will just stand there while most players will get out of dodge in a hurry.
The zee-lixir can be handy but Chompers are already getting good at faking you out. It's such a short duration of effect that if a Chomper burrows close by and you use it, they can just wait it out and then devour your host, stunning you and making you vulnerable. If you wait instead they may chomp before it explodes and still swallow a teammate since the effect goes after the chomp starts.
I didn't see anyone use that independent co-star bug last night and I when I played wizard, I made sure to use the two headed dragon build to see if it would happen and never got it so no idea how it works, and hopefully it's fixed before someone finds out how to do reliably.