Hu

There are a few holes in your theory. Naruto had access to the truth seeking orbs because he temporarily had a connection to Hagoramo's chakra after near death. Also, Kurama WAS his connection to the other 8 tailed beasts. He can't access their chakra remotely.

Blackbeard didn't "eat" the gura gura no mi. He had some way of taking people's devil fruit abilities directly. Shiryu is proof. They captured Absalom and took the suke suke no mi powers and gave them to Shiryu.

Not everyone. I'm ambidextrous. Lol. But, I do have certain hands that I use primarily for various activities like brushing teeth with the left. I will say my left has neater handwriting in print and the right is better at cursive. Theoretically, you should have the same strength if you train, but usually the dominant hand is just better at finer motions.

Wow. Strong opinions given it's just someone making a baseless assumption. If anything, I'd argue Hinata comes out with a new power. She is the rightful heir to Huga. Lol. But, she and Naruto are probably only going to be released after everything becomes peaceful again when Kawaki is subdued.

She can't awaken Perfect Susanōo. That requires a blood relative's TWO sharingan eyes. Quite a pity Sasuke has one(possibly still an intact 2nd...) Also, even if she tried the byakugo, it's effects are permanent because cells can only regenerate so many times. Especially complex ones like eyes. Tsunade only looks the way she does because of cosmetic ninjutsu. Her true appearance reveals itself when she's out of chakra and it's even more haggard than Jiraiya's appearance despite being the same age. But, despite not being able to be a full Uchiha, shes a strong ninja candidate for hokage.

Her medical process is lacking, though. She has Tsunade and Sakura's chakra manipulation, but hers isn't meticulous enough to utilize as a med-nin. Even in the anime she was outshined by others due to her inability to control her chakra under mental duress.

I disagree with the fish man aspect being mostly a bad thing. While they loose their swimming, they eliminate the whole drowning weakness of other beings consuming devil fruits.

You forgot that the Forest God is supposed to have "sent demons". I think it's more likely that Imu is the forest god than earth because he is in control of their yokai powers.

Don't forget about the various forms of leviathans out there. Lol. The cephalopod or Marco's fruit(btw, not intangible. Just quickly heals in flames) ideas work because I think a lot of people forget that the yami yami no mi also has another drawback: he takes in all pain and damage, regardless of haki. He's gonna need regenerative help when he's dealing with people much stronger than Ace.

Update: The quote that Gandalf the grey said to Bilbo was used in the most recent episode by Tom Bombadil to The Stranger. The one where he says "Many that live deserve death. And some that die deserve life" or something like that. Pretty sure that's a strong hint the stranger IS Gandalf. That and his fondness for the halflings and whatnot.