That’s thinking too negatively. Think of how great that’d be fighting a team, the ability to destroy unity, it’d be really helpful.Or how beneficial it’d be for your team, to destroy using unity, that sounds like it’d improve teamwork.

Because he’s a troll

Davesprite died early on in the voyage post-retcon

Yes

Sessions take place outside the Genesis Frog, they weren’t inside the frog when they left or when they arrived.

He’s getting ready to beat up his denizen

Alpha kids’ universe is in the same Genesis Frog as the Beta kids’.

As for why so long, John and Jade were travelling through an alternate dimension at a speed so fast that time slowed down, and The Meteor Crew were travelling through the Furthest Ring where time and space work differently and it’s incredibly difficult to navigate through.

She was controlling him in order to get the Ring of Life, and not very long

Also Terezi is still blind. 

Not yet.