The traitors won’t be sworn in “so that the coup is complete.” The problem with that idea is that if they are sworn in, the coup is complete.

The only way to undo it at that point is literally a military coup - we don’t want that either. (Well, WE would, but it’s a lot messier that way). Better to arrest them just before.

There also will not be a new election - there is nothing in the constitution about a “do-over.” More likely, Pompeo becomes President because of the chain of succession (assuming Pelosi and Grassley are both also arrested or otherwise disqualified.) Pompeo picks Trump as his VP, then resigns. Trump is sworn in and picks Flynn (or Pompeo) as his VP.