would lennox lewis go undefeated if he fought today

This....The very best Lewis is far to savvy, powerful and technically gifted to ever allow Wilder to get a foothold and as courageous as Wilder is, there's no way his chin holds against Lewis's heavy artillery. Let's not forget aswell that Lewis took bombs off Briggs, Holfield, Mercer, Bruno, Vlt Klit, all who could seriously crack so his chin is far from questionable, he just switched off on the odd occasion. I doubt very much he would do that against Wilder