It doesn't matter if someone has more points. This is after replenishment phase, so Groo could die and wreak havoc, wresting defeat from the jaws of victory. The Pawnshop can be used during Leftover Phase. The Marketplace only works on your turn, so it's irrelevant during leftover phase. The players may use only the cards remaining in their hands.
Event is drawn, then resolved, then replaced.
They are replaced immediately upon resolution. Moreover, one must draw multiple cards. If one needs to replenish three cards and draws an event on the first card, one does not resolve the event until all three cards are drawn. When Groo destroys buildings, the owner of the buildings chooses which he destroys. Same goes for armies.