You (or someone else responsible) have to be there tomorrow.
The parenthetical clause can be ignored in terms of the agreement, so you treat it as the sentence "You have to be there tomorrow".
Either my team or you have/has to be there tomorrow.
This one is trickier. Your best bet if you can't rephrase entirely would be to apply the proximity principle and have the verb agree with the closest noun or pronoun:
Either my team or you have to be there tomorrow.
However, some will object that "my team or you" are plural or at least seems plural-ish (as certainly "my team and you" is). There's an advantage therefore to:
Either you or my team has to be there tomorrow.
Because at least then both approaches will agree.
It still won't satisfy everyone though.
Better to just rephrase entirely:
Either you have to be there tomorrow, or my team does.