Is Ashura the actual creator of the "Rasengan"? So as you can see in the fillers, that when Ashura is helping out the other villagers, he is using a jutsu just like the Rasengan. 


Is this the Rasengan we know and love, or is this a different jutsu for say a wind release?
If it is indeed the Rasengan, then does this mean that Ashura is the original creator, and not Minato Namikaze?
If the second one is true, this could mean that Minato has some relations with the Ōtsutsuki?
It depends on what you consider canon. Almost all of the Ashura and Indra and even Kaguya backstory stuff was anime only filler. The manga has almost none of that. Thus, in the manga, there was no mention of Ashura ever using Rasengan, or pretty much any specific jutsu for that matter. Indra's eyes barely resembled a sharingan, and Hagoromo was never known to not have the Rinnegan. So in that regard, Ashura isn't the creator, its just anime only filler. They likely chose things like the Rasengan and Sasuke's Mangekyou and put them on the two brothers to try and make it all seem more like destiny or something, symbolism that things are repeating themselves. Its pretty low quality story and a plot hole because Madara doesn't have the same pattern even though he was also an Indra trans-migrant. The story wasn't about destiny, but instead about how Naruto used the power he was given to change things, when the world finally was ready for it.

If you consider anime filler canon, then indeed he is the original creator, but like another answer here points out, he didn't pass it on. Minato most definitely developed the Rasengan on his own. In that regard, they both are the creators, Minato just rediscovered it.