HP Doomsday
Kurse (who was invunerable except to uru)
Cyclops ( Visor off and Unlimited Get Off My Lawns)
Bor ( who is more durable than uru)
Classic Juggernaut
FP Kuurth
Colossunaut
Cyclops is a non factor, but the other guys should be able to beat SB-Prime individually, since the most recent version (the one in the last Teen Titans comics before DCnu) was depowered into oblivion. Wonder Girl alone was beating the crap out of Superboy-Prime who was ... bloodlusted (?), because he appeared in Conners universe and Laurie wasn't there anymore.
I'm telling you, that entire "arc" was so damn, it really made me angry. The stupid reasoning, it was so bad. Sooooo bad.
He is not going to harm the physically invulnerable Juggernaut, but I'm also not sure if Juggernaut would be able to do something to Prime. I think Prime could shrug off most of the damage pretty well and even if he starts having problems with it, he could simply fly up and take a good amount of solar radiation and then he would be there to fight.
Just because he can't harm the Juggernaut, it doesn't mean that he automatically loses, since no one without uber-physical strenght and telepathy would be able to defeat the Juggernaut, if BFR is not allowed.
Prime would pass the round with classic Juggernaut, for obvious reasons.
If Prime gets solar recharge this could last a while. Really this comes down to Classic Juggs Bor HP DD and Kurse. Kurth gets boned if Prime jacks Bor's weapon IIRC he's had a sword and axe I believe they were uru. Classic Juggs I just can't see tagging Prime but conversely I don't see Prime stopping him either. Bor has a proven durability limit though and if this fight is in broad daylight I see him potentially though entirely unlikely going down. Prime loses overall I think between Bor Juggs and HP DD there really isn't much he can do even ignoring everyone else.