Probably you added them because they share the same "skeleton" (or body shape), but that's no longer properly valid in the latest MH Games (An example are Gogmazios and Magalas, same skeleton but they're not releated at all).
Who knows, maybe Tobi-Kadachi and Odogaron may be releated but we need a solid proof of it beside same body shape and a couple of attacks in common.
Barroth is in no way related to Gureadomosu. Gureadomosu is a desert-dwelling Gravios relative, while Barroth is a Brute Wyvern. Your other edits were reverted because, while not outright implausible, it's not directly confirmed by Capcom those monsters are related to each other. Please do not add speculation or guesses, this wiki relies on official info only.
Drake my edits had nothing to do with the way a monster looked relative to another monster, in fact that has nothing to do with monster relations. nor does the way a monster acts inducates its relation to another monster... smh.
An official tweet would be fine, if you could provide a link to it to prove the screenshot wasn't fake.
To which I'm inclined to believe that screenshot you just posted is indeed fake, as the official @monsterhunter Twitter account doesn't post Japanese tweets, no posts on that day mentioned anything about Deviljho aside from the trailer post, and the fact that the link present on your screenshot leads to nothing.
For someone who talked about being factual, you're doing very little at being so yourself, if you want to prove you are then post the link to your tweet. If you're unable to do so, or unable to prove any of your other claims then I don't see a need to keep this thread open.
I'm no admin, but I could have sworn that the burden of proof was on the accuser and not the doubter. If you're not going to provide evidence of your claims, but instead belittle the people asking for citations, that indicates that you have no argument to give and are just trying to save face. Anecdotes alone aren't enough to prove a claim, and like MHCaboose said before, your claims just don't add up, so it would be wise for you to either provide the citations or back down.
I don't think you've ever talked to me, so... Hi!
I was just checking through your profile today, I and I saw something quite familiar.
Are you the Karasu from the Monster Hunter Stupidity videos?