I've some general questions that seems to be jumping around with different answers, so here they are:

Are the Aedra and Daedra gods at the same level? I've read that the only difference between them is that the Aedra contributed with the formation of Mundus, leading to say, the Daedra can be even more powerful than the Aedra, considering the events at the end of Oblivion. Some references:

• "aedra has been weakened quite a bit, after creation of the world. Daedra just sits back, keeping their full charge."
• "Daedra would probably lose, seeing as how an avatar of Akatosh banished one of the strongest Daedra Lords. Besides Daedra can't really leave their plane of Oblivion, only influence mortals to do their bidding."
• "Im not sure if this is correct, but I remember reading from somewhere around two years ago that Aedra (The 8th specifically, I guess) are more powerful than Daedric Princes. So guess they would win at least at first. It was also mentioned however that Daedra as you may already know cannot truly be destroyed as far as we know. Only banished. While Aedra apparently can be undone by violence. Mind you, you'd probably need to be pretty damn uber to manage that, but if you do somehow.. guess they would stay dead."

Can a Daedric Prince be destroyed on Oblivion? Some say that when it is defeated the soul will go eternally on an endless void sort of thing. Another version is that the one who defeat the Daedric Prince will take his place as happened in the Shivering Isles. Some references:

• "The Aedra are presumably weaker than Daedra since they diminished themselves in the creation of the world. Dragons, even Alduin, are powerful but not actually divine - their powers are great but limited, while Daedra appear to be effectively omnipotent in their own realm. Even if one Daedric Lord were able to invade another's realm, the invader would likely be weaker due to being separated from their home plane. As a result, they would be defeated, banished back to their own realm, and nothing would be settled."
• "If they are killed, especially on the mortal plane, their innate spark of life, what is sometimes called their "soul", returns to a new physical body. However, there is a portion of the universe, the true void, which is outside of any of the planes of existence; when a sufficiently powerful being manages to kill a Daedra in their native plane, their "soul" is lost to the void for recycling in a similar process to the dreamsleeve."

How powerful is Alduin? Considering him at his full power, can he can beat a Daedric Prince? Considering the Leaper Demon King story and else, doesn't that mean the Daedra are not as powefull as the Aedra? Calling Mehrunes Dagon a god where does Alduin go? Some references:

• "Mehrunes Dagon is a god. he existed even before the realm that Alduin devours existed. He MIGHT even be stronger than Akatosh because akatosh and the other "gods" gave up so much of there power in creating the mortal plane that they are bound to the mortal plane and can't even manifest without a host."
• "Alduin would defnitely win this fight. For reference, see the end of TES:IV. Akatosh's first-born can probably be assumed to have roughly the same powers as his earth-bound avatar, which defeated Mehrunes Dagon (albeit a Pyrrhic Victory)"
• "Alduin is on a whole 'nother level, and actually created Mehrunes Dagon, one of the most destructive princes. A better question might be "if all the Daedic princes united (which is so unlikely as to be nearly impossible), could they destroy Alduin and stop the Kalpic cycle? Or would that require the destruction of Akatosh and time itself?"".
• "Alduin is a god in the sense that the sun was a god to ancient civilizations, he's not a god, he's just the oldest and most powerful Dragon and has a portion of the power of Akatosh. Mehrunes Dagon is a bonified, unkillable, limitless power, god."

If a Daedric Prince can be Destroyed it hasn't been found yet even by the Princes themselves or Jyggalag would be dead proper and not Cursed to be Sheogorath.

So I suppose you'd like us to say who is more right? Or would you like our own, different answers?

Your answers, as I said there, the quotes are references. In case you wanted to know why I said there were different answers everytime.

As I suppose in Lore there should be a correct or more guided answer away from things that aren't settled as the reply by Arthas suggested.

Are the Aedra and Daedra gods at the same level? I've read that the only difference between them is that the Aedra contributed with the formation of Mundus, leading to say, the Daedra can be even more powerful than the Aedra, considering the events at the end of Oblivion.

Yes, strictly speaking. The Aedra and Daedra are known as the Et'Ada, or Original Spirits. Original in that they were the First, born of the interplay of (or lack thereof) Anupadomay. The Magne-Ge, those who took part in Creation but later abandoned it, are also part of this group. They are of varying degrees of power, however. From godlike beings such as Akatosh to the lowly scamp. As to who is more powerful, Aedra or Daedra, I'd say its a false dichotomy. The Aedra aren't exactly still around in the same manner that the Princes are, so any "fight" might result in forfeit. I suppose you could make an argument that the Aedra are manifest in the values they project, and by doing so claim that all the Divines had a roll to play in casting down Dagon at the end of the Oblivion Crisis.

Can a Daedric Prince be destroyed on Oblivion? Some say that when it is defeated the soul will go eternally on an endless void sort of thing. Another version is that the one who defeat the Daedric Prince will take his place as happened in the Shivering Isles.

Destroyed in Oblivion? No. Defeated? Certainly. The Hero of the Battlespire banished Mehrunes Dagon from that realm by effective application of both Dagon's protonymic and neonymic. While Sheogorath's Champion defeated Jyggalag in open combat on the steps of New Sheoth Palace. As with all Daedra, with defeat, their animus is cast into the Waters of Oblivion - a terrible place of pain, fear, and confusion - until they can find their way back to corporeal form. You do not take a Prince's place upon their defeat. The circumstances in the Shivering Isles was unique. And you do not take the place of Jyggalag. But rather you assume a role left vacant by him. A role you have grown to fulfill.

How powerful is Alduin? Considering him at his full power, can he can beat a Daedric Prince? Considering the Leaper Demon King story and else, doesn't that mean the Daedra are not as powefull as the Aedra? Calling Mehrunes Dagon a god where does Alduin go?

Beyond knowing that his power resides beyond that of a "normal" dragon, we know nothing concrete. Much has been made of his Akatosh pose and his soul's departure in Aetherius, but little has been bore out as of yet. Shalidor names him as the "creator" of "dragon civilization" and First-Born (a title born out elsewhere in Skyrim), but what that means to a race that, according to the daedric dremora, are "eternal, immortal, unchanging, and unyielding" no one has a great answer for. As near-immortals, this may mean he is Et'Ada. Or even perhaps the amongst the first generation of their descendants. As to how he might compare to Dagon, it is impossible to say.

Thank you very much! Now is more clear