Well considering the type of feats Naruto showed, I doubt Madara could kill him.
The guy is an EDO who looks like thanks to a Hashirama technique managed to do that harm to the kages. And no, he wasn't letting anyone to just hit him. If he would've just played, it wouldn't have been necessary to pull up a Perfect Susanoo, which is granted thanks to him aquiring the Rinnegan.
You'll say perfect Susanoo is comparable with a Bijuu.
Bijuus are 9, so we can assume it can be any of the 9 Bijuus, not necessarily the 9th one.
Madara is speaking that way because his personality is cocky. Probably that's why he lost to Hashirama.
The first and the second probably couldn't because Orochimaru didn't let them roam free, like Kabuto did with Madara. I know they were powerful, Hashirama is in the end the one who won over Madara.
Well, Sasuke is still under development and is fairly known that him and Naruto will be the most powerful shinobis in the unvierse, so no necessity to bring him up into the discussion as an example because all the things will be build around him in order to favour him.