If every player controls a creature when the ability resolves, the ability wont do anything
Similarly, once the third ability triggers, those creatures will get +4/+4 when it resolves, even if one or more of those creatures left the battlefield
The companion ability has no effect if the card isn't revealed as your companion at the start of the game, and it creates no restrictions on putting a card with a companion ability into your starting deck
Watching everything you play immediately die could quickly turn someone off of Thunder Junction
Then, of course, you'll get a couple other goodies, like a spindown life counter to keep track of your life total
I think I'd get rid of spells like Reap What Is Sown and Common Bond