1. Team 1 comfortably. Valkorion is more deadly and capable in the Force than Yoda for sure. And Arcann is solidly stronger than Windu.
2. Team 1 with some effort. Again, I just think they're plain better than their counter-parts. Like with the Outlander, Arcann can handle Windu in sabers enough to win with his Force powers. He doesn't use dark side techniques to proc Vapaad either I don't think.
An interesting idea would be if Yoda fought Arcann and Windu fought Valkorion. I think Valk can overwhelm Windu in the Force offensively given time, but I also think he could probably easily turn him using TP. Windu already skirts the darkside and has no notable resistance feats I can recall (wasn't just being on the planet in Shatterpoint f'ing him up mentally?) so it should be Revan and Malak all over again. Yoda would similarly beat Arcann without much difficulty. But with Windu at his side Valk crushes.
Round 1 seems to favor team 1, actually. Valkorion's about equal with Yoda (although Valkorion would be the one to win a majority in such a fight, I think) and Arcann is probably somewhat more powerful than Mace and certainly more durable. He'd take Mace down after a long and brutal bout.
Round 2 is where team 2 makes a resurgence, since Mace can now take the lead over Arcann and Yoda has a better shot of taking down Valkorion.
LOL this might be the most inaccurate accusation you've ever made about me.
I personally love watching OCW. It really shows how the Jedi should fight imo. Given the hype these characters get, the movie characters are presented in a very humble medium compared to the rest of EU despite their importance in the lore. More importantly, PT/OT isn't a climax like the LOTR trilogy where the modern characters are infinitely inferior to ancient beings. On the contrary, some of the climax era characters appear to be the peak of their alignments in the force until that point in history. With this context, guys like Mace Windu having his OCW feats isn't really absurd and RoT power-scaling correlates with this. It doesn't change the fact that it contradicts higher canon, and there is room for doubt though.