X-factor definitely upgrades as you lose characters, this video is higher quality and you can see the icon get bigger when more characters are down. You can also see a DHC in this video at around 2:25 when Goku switches with Gohan. This is looking like straight up Marvel 3 gameplay and I for one could not be more excited.
BTW I don't really know DBZ but I see everybody teleporting all over the place in these videos. Looks like it costs 1 meter. Is that a common power in the anime?
Yeah, they teleport pretty frequently when fighting. It's not really considered a power aside from one specific case being a special move of sorts.