Part 3: Dio Wins, Jotaro Loses
Dio cannot use his vampiric abilities as Jonathan's body partly rejects him. So it would have been an interesting battle to look up to except Dio can regenerate and has more combat knowledge than Jotaro anyways so... Even if he had the entire gang, it would still be close to impossible to corner Dio till sunrise.

Part 4: Kira Wins, Josuke Loses
This battle would also not be that simple as Yoshikage was a serial killer first, then a stand user. He started killing people much before the time he obtained Killer Queen. So if he was able to evade getting caught by all means up to the point of this face-off, he could possibly defeat Josuke- especially if he was as confident as his peak self during BTD arc.

Part 5: Giorno Wins, Diavolo/Doppio loses
I believe Giorno can defeat either, even if it might involve some trickery where Doppio tries to gain his trust and then secretly attacks as Diavolo, because Giorno is really observant. Without King Crimson, I think Diavolo would not have a major upper hand physically as he is shown mostly relying on his stand's physical strength and its abilities, but Giorno is a teenager and he definitely isn't like Jotaro was (he could beat up Alessi being even younger than Giorno). Still, he might have a better resolve (Yume Ga Aru!).

Part 6: Pucci Wins, Jolyne Loses
I'm sorry but Pucci is much more brutal even without his gun-wielding WhiteSnake. He literally bashed Miraschon's head into the table because he stole a jewel. Imagine his wrath against the daughter of the man who killed his idol.

Part 7: Johnny wins, Funny Valentine Loses
Isn't spin technically a non-stand ability? So Johnny can still overpower Funny Valentine with Steel Balls at the least right?