It is too early to tell wether Ash will keep his Unova team with him or not for the next 6 gen region.I highly doubt that Oshawott would be the only one he would take with him since he does have Tepig and Snivy,he would take all three of the Unova starters.It's way too early to tell that Ash will keep the Unova starters with him, considering that he's around halfway through his journey. But then again, Ash only has Pikachu with him when he goes to a new region, but I think that Oshawott might secretly follow Ash and join him, like Aipom did in DP.
I have a feeling Juniper Lab since we say Tranquill there before. Either way like I said before whatever scenario that plays out they won't be on his team for long because they are out to promote new pokemon and they can't very much do that with people from the prior generation unless they have a new evolution that generation like Aipom did when he went to Sinnoh.I think that he'll make a fresh start. Meaning Tepig, Oshawott and Snivy will stay behind. Where? Who knows. I'm hoping they go to Oak's lab so they can interact with his other Pokemon. He'll start his new adventure with just Pikachu. I wonder if Oshawott may stay with him. Since it's quite attached to him.
I have a feeling Juniper Lab since we say Tranquill there before. Either way like I said before whatever scenario that plays out they won't be on his team for long because they are out t promote new pokemon and they can't very much do that with people from the prior generation unless they have a new evolution that generation like Aipom did when he went to Sinnoh.
That is PlatinumDude opinions,there is no way Oshawott will be the only one Ash would take with him to the next 6 gen region,he could take all of his Unova team with him and it don't matter about them promoting new pokemon either. The reason why Aipom went to Sinnoh with him was due to it having a 4 gen evolve form and they also did it to promote the 2/4 Gen pokemon games aswell.The poll is multiple choice xD
Back on topic, I have doubts to bring back specifically one of the three. But then again, it the series is becoming more dynamic and a tad unpredictable, so its still a slight possibility. Like PlatinumDude said, it could just end up like Aipom.
I'd like to see them follow Ash to the Gen VI region although Ash mainly starts with only Pikachu in most cases.
He could have Snivy, Oshawott and Tepig follow him like Aipom did.
I'd also see him rotating Pokemon caught in Gen VI region like he did in Unova.
Yes but, if he took all of them he'd have 4 Pokemon straight away; at least with Aipom he only had two, plus Aipom got an evolution so they needed to showcase it. And like Kenshin mentioned; they would need to showcase Ash having Gen VI Pokemon.
But what I mean is, he could be rotating them with his older Pokemon and the Gen VI Pokemon so viewers could see some of his older Pokemon again.
Plus, he always catches a regional bird and a Grass, Water and Fire Pokemon (mostly starters).