I don't agree with your first point. I seriously doubt anyone would be able to break free of the Eternal Tsukiyomi given that it involves the usage of 10 tails to cast the illusion, not even uchiha. In my opinion, Tobi just massacred the clan to make his Madara disguise more believable, as Nagato pretty much told him to buzz off when he said he was Madara. We know that Uchiha betrayed Madara when he lost everything to fight for them. Such a man would only resent them.
He attacked the village by controlling the Kyuubi like Madara did which hashirama, and then help Itachi massacre the clan. Because of the similarity in patterns and the hate for the clan even being an Uchiha, he fooled Itachi even, making him believe he was the real Madara.
I agree with this point 100% though:
How come you agree with that post but you don't think Eternal Tsukiyomi can be broken?
I'll explain why I think it can be broken by an Uchiha. The info we've been fed so far about Tsukiyomi said only that is a very powerful Genjutso were the user has total control over the reality the target is perceiving. In other words is a genjutsu where all aspects can be manipulated.
Itachi's Tsukiyomi is by far the strongest, Itachi was able to stretch the experience up to 72h AND his Tsukiyomi could only be broken by an Uchiha eyes, a close related one. As for the brother bullshit it's purely fanboyism. All we have is close related, which mean that could have been a father or maybe an uncle or cousin... We don't know how close related it would have to be. I'll admit that in the case of Itachi's it might have been needed either the brother or the father.
But no where else is it stated that Tsukiyomi can't be broken, actually we've seen Bee breaking Sasuke's Tsukiyomi fairly easy and that goes to prove that not everybody has a Tsukiyomi as strong as Itachi, and frankly not even Madara as been counted for as a master of Genjutsu. :/
Now as for why the "Eternal" part does not deny Tsukiyomi's downfall. The reason why the Juubi is needed for the MEP is because Madara and Obito intend it to be eternal, Itachi bared a huge chakra toll each time he used Tsukiyomi and the farthest he pushed it the greater the toll.
Now Itachi only used Tsukiyomi one person at a time and one person was a job large enough so that we could estimate that 3 Tsukiyomi's a day would be like reaching close to all he had to give.
Bare with me a little longer, imagine the toll it would take on the user, chakra wise, if the user wanted to cast Tsukiyomi for 144h to three persons at a time. The chakra toll this would represent would be 2 times as much as Itachi could bare before going 0 chakra.
Madara and Obito want to cast an ever lasting Tsukiyomi on everybody!! The cheer chakra toll alone demands infinite chakra supplies!
Putting it in simple math you'll need millions times infinite amounts of chakra. This is why the Juubi is needed because of the cheer amount of chakra needed to cast the technique.
Now all of this does not imply that the Tsukiyomi it self would be any stronger.. in fact the Eternal Tsukiyomi it's remains, although eternal, only a Tsukiyomi.
There.