Ciatterelli will most likely win given that the two pro-Trump guys are tearing the other down. Also the ballot line system in NJ gives the establishment pick a big advantage in primaries.
However given how insane parts of the GOP are these days I can't completely rule out Singh winning, even though it seems so improbable.
Yeah, depends on what the GOP electorate looks like today. If the Trumpier part really comes out in full force, there could be a surprise.
Likewise though, if Citarelli ends up getting like 50-60%+ or something, that could mean the Trump voters are depressed and not coming out (signalling further that without Trump, they don't come out)