About the "best of" videos, I concur that they should be put on the main channel, at least as an external playlist or something (dunno if they can do that). There are probably legal ramifications they have to consider though.
As for what to call the second set of videos, I don't have strong feelings either way, but I do think that they're weaker than the main series, i.e. you're doing a good job choosing the best moments for part 1 videos, so having them all together may water down the quality a bit.