lewis without a doubt. Fury is as unproven as a champion comes. He has beaten a couple way past prime fighters and a couple bums. Wilder was only a year and a half younger than lewis in the klitschko fight ( when you brits all claim he was old and shot) for the last Fury fight. So the last fight Wilder was old and a career bum.
Purely jabs, Fury wins. Lennox may be able to have an effective jab because he can make Fury wary of everything else he brings. If Lennox can stun Fury with a left hook early, he will win the war of the jabs. If Fury can elude the left hook, he will be able to out jab Lennox with his greater reach, faster feet, faster hands.
I like Fury but Lennox is faster, more agile, stronger and has a wider array of KO punches. Even the Fury vs Wlad couldn't do that. Lennox was way better than both of them. That said Fury is the best right now.
Fury has better Height reach and weight Than Lewis. I Would also say better Speed and feints. As for power i think they are somewhat equal. But think Lewis edges him there. The thing with Fury is that His opposition looks Broken in a couple of rounds. Chisora 2. Whyte. Wlad etc. And they are very tough fighters otherwise. Fury has more finess.