As usual, the Stupid Party even screws this up with a split ticket.
Because this is a replacement nominee, it's a lot tougher to split things.
What's going to happen is, once they get Collins off the ballot, the party bosses from each county are going to get together, go over the candidates and pick one to represent the GOP in November.
There are three parties that Collins was running on: Republican, Conservative and Independence. The last of these is fading into pretty close to irrelevance. The Conservatives still carry some clout, but the names being considered on the GOP side so far are all pretty solid conservatives, and I don't really see any objections the CP would raise to any of them, so I suspect the cross-endorsement is a given at this point. What might happen is some horse-trading: say, they might agree to have Bellavia run for Congress, then have Mychaijliw run for county executive next year as he was originally planning to do.
The only split there really is to worry much about is the Reform Party nominee, Larry Piegza, but he's underfunded, has no real name recognition, and is pretty much a non-factor.