By the way, before the next question is asked I'll answer it. If a vote is approved, and if the vote ends in a tie... no - VP Vance can't vote to break that tie. Only the sitting senators of that party (in this case the republicans) can vote since it is not an official Senate vote but a private caucus vote.
Vance can't convene the senate, only the majority leader can do that.
By the way, before the next question is asked I'll answer it. If a vote is approved, and if the vote ends in a tie... no - VP Vance can't vote to break that tie. Only the sitting senators of that party (in this case the republicans) can vote since it is not an official Senate vote but a private caucus vote.