Wow. Old thread. Funny though after nearly 5 years, the shikai question is replaced with a bankai question. It is likely to be revealed very shortly but we still don't know it. While I do think Ulquiorra would beat him, we can't be sure yet.
Naruto characters overwhelmingly aren't fast. Unlike the majority of bleach characters and most OP characters of relevance, most Naruto characters haven't demonstrated a dash or blitz movement skill like shunpo or Soru. Body flicker does exist but a select handful actually have the skill.
Plenty of characters in all 3 HST have defended attacks they didn't see with their own eyes, and many have sensory abilities that allow them to react better than normal, but to imply that Hashirama could rely entirely on chakra sensing without vision not only hasn't been shown, but is a massive stretch to say the least. No sage character has battled blind and until they do it's too much of an assumption.
He was ambushed. You remember the path that attempted to absorb his power? He caught him from behind. Also all the examples you gave involve seeing the enemy directly with their eyes and all their senses for that matter, little evidence of relying on chakra sensing. Again there hasn't been an instance where in mid combat, someone relied entirely on their chakra sensory abilities including Hashirama. If it were that easy then why not do that with Madara who was unable to overpower his defenses? Nobody has done this in Naruto.
That's more like reiatsu sensing which gives a vague idea of where people are not a fully competent sense like observation haki. It's essentially sensory skills. We've never seen a shinobi in Naruto sense on the level of knowing exactly what the enemy is doing movement for movement as if they were seeing it with their eyes. Naruto in sage mode was still ambushed by I believe it was the Nakara Path and Jiraiya in sage mode failed to sense the other paths of Pain which would've saved his life if he'd known about them. It can't substitute seeing Starrk.
I don't know since I don't see him as strong enough or fast enough. They were even individually quick and strong enough to corner end of pre time skip Zoro. He did eventually beat them all but I doubt Kisame is that strong.
I'd say he loses scenario 1 pretty badly. I don't think he has the strength and speed to deal with them. His water jutsu are handly but I don't think he can spam them fast enough. Scenario two would be barely different as Zabuza probably can't take even one of them. Scenario 3, they put up a good fight but still lose. I believe they all together lost to Kakashi and Lee off screen and those two weren't even hurt.
Yes. Killer Bee's durability is high I will admit, however he's shown weakness to sharp and piercing damage as pre EMS Sasuke was able to cut off a tentacle with a mere chidori blade. Mihawk's slashes are around Final Susanoo level. At least in that ballpark.