In that second vote, in the name of avoiding any bad blood from the previous contest, I'd argue for a rule that none of the candidates in the last leadership contest could run again.
This is preposterous, unconstitutional, and anti-democratic. For federal council to unilaterally disqualify candidates from the last round to avoid "bad blood" would put a stake through the heart of the party. The most recent leadership race wasn't nearly as bloody or bitter as 2012's, and yet nobody was banned from the party after that one. Not to mention the precedent it'd set: Hey members! Not a fan of anybody in this race? Don't worry. Pick the one you think will be weakest, undermine him/her, and within a year we can get a do-over s/he'll be banned from running in.