uffy at least could possibly fight with an Admiral evenly now
That is one pretty big IF. Lets not forget that not only are the admirals and fleet admiral ridiculously powerful Lofia, all of them have Haki as well. Akainu was the most injured in the war since he decided to tango with WB, and was caught off guard by WB.
If Luffy fights Caribou we will be getting confirmation that he can fight a logia effectively, although it is a formality at this point since we know how Haki works. But Caribou is obviously vastly inferior to any of the admirals, I would go as far as saying inferior to Smoker.