There have been a number of conservatives which have joined the Democratic party and they all say that they remain conservatives. Historically this is not possible because the Democrats are against almost everything conservative. I don't think that those folks will do too well as Democrats unless they can be converted. How they blend in with the left wing of the Democratic party is even more doubtful. All that being said I suspect there will be a bit of infighting until it all works out.

The Trump thing is a brand new thing. If Trump goes away those remaining Republicans have no real home and the Democratic conservatives can return home.