Well, there are several possible options.

Your character's father can be an Altmer who was born in the Dominion but chose to live in Cyrodiil and be a citizen of the Empire. He can still teach his son the Altmeri manners and culture. But in this case, he and his family would most likely see the Dominion as the enemy.

Another option is that your character is an Imperial born in the Dominion and raised in the ways of the Altmer. If he also has an Altmeri father, that would mean that he is a bastard child and his parents aren't married. His father also may or may not have an Altmer wife and other, Altmer children. In this case, it is likely that your character is a very devoted follower of Altmeri ways, to the point that he agrees with the belief that humans are inferior to elves (it is possible). Basically, it's an Altmer in all but blood.

The wiki is extremely unreliable, and this quote shows that very clear. If you want reliable data, go to the UESP.

The last sentence obviously refers to the events of ESO. The 4th Era Altmer definitely wouldn't let any other races raise to nobility in Alinor - they have had more than enough of that and what that entails, during their time under the Imperial rule.

It is true that there are dissidents who are against the Thalmor (ironically, it's almost the same situation as in ESO, only this time they fight for an exactly opposite cause).

The Altmer who live in the Empire apparently like the Empire, no? Lol, I can write you a word wall about all the possible nuances of the situation with the Altmer and the Thalmor, but I doubt that here is the right place for it.

An Altmer came from the Dominion to Cyrodiil because he didnt believe the "Mer are better than Men". He is a Citizen of the Empire but honors his Altmeri culture. He marries an Imperial Woman and they have a Son. When the Kid is a preteen (arround age 9 to 12) he is asked what culture he wants to inherit. He chooses Altmer and gets his Altmer name Teliotar and drops his old Imperial name Telrentor Cecades. He is then taught about the Altmer Culture and Believs by his Father. He understands the hate for Tiber Septim but he disagrees with the Dominion point of view.

The world doesn't revolve around men, you know))) Some Altmer have reasons to oppose the Dominion without even thinking about men. These reasons can be economical, religious, tied to the subject of who ended the Oblivion Crisis, purity of blood, personal beliefs, etc., etc. Plenty they are.

I would say that by marrying an Imperial woman he betrays his ancestry and claiming to be honoring his Altmeri culture after that is somewhat of hypocrisy, but some people are that way. It would be really weird for the kid to change his name though, if you want him to have an Altmeri name, why not have him simply have it from the start? Tbh, it's a really tricky concept all in all.

So, to spare you the possible inconsistencies, let's start from the most basic. What kind of mindset you want this fellow to have? What kind of person he is, what he believes, what are his goals?

Well im still planning most things for this Character, but i wanted to get help on the Altmer stuff before i finish it to avoid making big Lore Mistakes :D

That with the Name is Right i should just give him an Altmer Name youre right. What i meant was for the Father to pass on his Believes from his days in the Dominion. Things like seeing the low class Deadra as Neutral instead of good or Evil, Teaching him about the Altmer Gods like Auri-El and Magnus Showing him the Elven point of View on Talos. But He does not Agree with the Dominion. Is the Dominion and basic Altmeri Believes like Believing in Magnus really so intertwined that you cant seperate them?

The Dominion and the Altmeri culture are not really tied together. The former is a state and citizenship, the political stuff, the later is a culture and a religion, more personal stuff, it's not the same. Most Altmer don't see Daedra as neutral, they think them evil 100% (and they are right). But if your Altmer dad dislikes Talos so much that he would teach his son to dislike him too, why would he live in the Empire, the country that worships Talos as god? What is his issue with the Dominion? Every one of these things should be examined separately, no?

I Thought the Empire was under the White-Gold-Concordant? I just checked and the Deadra thing was a post on the Imperial Library. I thought it was a Book -.- 

Everythings falling apart, Might aswell drop the Altmer Part of the Character since i dont know whats actually canon and whats not. 

The people's worldview doesn't change overnight. The White-Gold Concordat didn't change the whole Imperial mentality and their beliefs, it is only a law.

Was it a book about Psijics? They are the ones who might see Daedra as neutral, but not the common Altmer.

Nothing will fall apart if you determine what exactly you want with this character. Everything should have cause. Choose a few main facts about your character that are the most prominent and important about him. Then build the backstory based on them. I really really don't want to put a wall of text here, if you want help on this, you can PM me.

Well i Know the Basics of The Character but i didnt know all that about the Altmer. Thought it was a cool Idea to have an Imperial Understand where the Thalmor are coming from but if i have to jump through all these hoops just to justify the Father then i dont know if i Should even Include that. 

Feel free to PM me that Wall of Text i would like to Learn more^^