There might be a problem with John Smith :-)
Rumour has it if Johnson were to return he'd actually reach out to the top talent in the party. Rather than doing as he previously, and Liz Truss, did namely fill the cabinet with your mates and political soul mates. We definitely need people in the cabinet for their ability, not just because they've been promised something in return for a vote.
It seems as though the election will go to the members unless there's only one candidate who gets 100 nominees. If there are 2 remaining, the MPs vote, and then the members.