Maybe I saw different interview, but in mine Fury told that due to there were no videos of Ngannou real boxing fights, they did not know what to expect. All the knew Ngannou has speed and power. Not much to build tactics on. Well, if on October 28 we saw prepared Fury, who fully understood what to expect from Ngannou, then no doubt he would have huge troubles against Usyk. My offer if Fury should have a rematch was more addressed to those who say that Ngannou won 
But in general I would love to see fight against Usyk, then against Ngannou.
But in general I would love to see fight against Usyk, then against Ngannou.I was referring to this interview: https://www.youtube.com/watch?v=YTOFDVNzMM0 in which he said both, that he came prepared and didn't underestimate Francis, and also said what you've mentioned, that they had no clue how good or bad Francis was in boxing.
Nevertheless, if a man who had no previous boxing fight just casually knocks down the lineal champion and was close to winning the fight - this puts a dent in boxing as a sport and Fury definitely has something to prove here. It's in everyone's interest to see Fury getting the job done right.
Maybe he can say all he want as the fight is already done, but we really don't know what's behind when he is training. He might be training hard but there could be a lot of distractions from his family specially his father. There's also reports that his brother said that he will take over the training of Tyson, so it could be another indication that something is not really right when he did prepare for the Ngannou fight.
Obviously, if I had to choose between Fury Vs Usyk and Fury Vs Ngannou 2, I'd choose Usyk, but there's no reason we can't have both of those fights (Usyk first, Ngannou later).
Fury vs Usyk make sense for them, it's for a unification fight. It's been a while since we have seen someone holds all the belt in the 4 belt era so that will be big for either Fury and Usyk and it could cemented their legacy in the heavyweight division. So Francis can't do anything but to wait for Fury and Usyk or even for AJ and Wilder if he also target those big names for huge paycheck.