Well, I think inarguably Kizaru would lose, as Rayleigh was able still, at a minimum, match him as we saw on Sabaody. If Roger's First Mate, well after they conquered the seas and thus almost certainly past his prime, could hold his own, then I feel fine in saying Roger would trounce Kizaru. I think he'd have more trouble with Akainu and Aokiji, and I don't think Fujitora would be very high on the challenge meter.
The Yonko, on the flip side of the question, is an interesting hypothetical. It's stated he fought to standstills against both Garp and Whitebeard. I'd be blown away if Shanks ever would fight his Captain, and even then I think if they fought, even a two-armed Shanks would lose. Big Mom would probably be a harder fight, but with Linlin, it depends on the battlefield. If she has her Homies, her children, and her crew, Roger would have a hard time winning, but to be fair, we've only seen less than a dozen of his crew members in action. Because of that, I think it could go either way if it was a full-blown battle, but in 1v1, Roger wins. Kaido is the same way if it was Roger Pirates vs Beast Pirates, but he would be the hardest opponent in single combat.
I completely forgot about Blackbeard until just now, but unless nothing short of divine intervention happens, Roger would have a new rug for his living room.
