Yes, exactly. And since he is in his body (and technically alive) the Ideal Masters can't really make use of his soul. And why is that? Apparently because it's too big for them to handle.

And we also never heard of anyone other than a Dragonborn to be able to absorb a Dragon Soul. I mean its how you can easily spot a Dragonborn.

Also true.

Yes and i appreciate youre answer i was pointing that out. A possibility i could see is you dont absorb them but offer them to lets say Herma Morawho will then give you the Knowledge of the Dragon.

You cannot do anything with a dragon soul unless you are Dragonborn. If there was a way, the current dragon problem in Skyrim, as in Alduin resurrecting dragons by handfuls, would not occur. However, I don't see why you cannot just have Mora teach your guy a shout, without dealing with any souls. After all, the draugr hardly absorbed any dragon souls to learn shouts. Nor have the Greybeards.

Hmm youre right i could just ignore the absorbing.

Would a character who sides with the Thalmor (not an Elf) join the Imperial Legion? Or would they just let the Civil war alone

A Thalmor definitely would leave the war alone, unless there are some additional factors involved. If such a character is a soldier of the Legion, that would mean that he is a traitor, lol.

Ok thanks ^^