Yeah I should be good to go sometime between 7 and 8, not sure exactly when.
I don't remember there being anything you need to play before jumping online. The levels are the same whether they are in single player or multiplayer, however the progression is tracked separately for them. This means that completing a world in multiplayer won't unlock the next world for single player and vice versa. In single player, you still have three Links, but the other two don't move and you swap control between them. Pretty clunky, I don't recommend it.
Personally, I think it's more fun to just jump in headfirst and start playing online with us. Who needs practice? Learn on the job! It's always a good way to gain experience or at least provide entertainment for anyone watching. It's a cooperative game anyway so you've not competing with anyone.
I wouldn't be free until later. Will see how it goes once my certification class is done.
That's fine because the game is limited to 3 players and we already have 3 lined up to start with. If one person wants to quit before the other 2 then maybe you can sub in for them.