I'm not sure why this is relevant. Regardless of whether Alex votes second or last, Nina and Nico's best play is to both vote for one of Alex's permanents, which will result in them at the very least tying the vote and exiling something they want to get rid of in addition to whatever Andrea wants to get rid of. If Alex controls no nonland permanents, then Nina and Nico's best play is to both vote for whatever Andrea voted for so as to not lose multiple permanents, rendering Alex's vote moot no matter when it occurs.
This isn't something that's going to realistically matter in an actual game–anything that would cause the exact player order of the vote to matter would also push the case so far into the corner that it'd never find its way out. If you'd like to discuss and theorize about corner cases like this, I'd suggest taking it to
Rules Theory and Templating on the Wizards forum; it's not really something that we want cluttering up the email inboxes of half the certified judges on the planet.