Exactly. They had an hour.
There may as well be none, but discounting it from the playtime they had is mighty silly.
My fear is that there is there is no mention of such features in any of the marketing. Whoever's in charge might simply not prioritize this over "self-insert into South Park". South Park has a ridiculous international fan base anyway, so why bother?
However many collectibles and side-quests this game might have, if the player can do everything in one playthrough, replayability will suffer. I mean, if the only difference between playthroughs is PC's class, and if that only affects battle mechanics and some spoken lines, that's not enough.
Of course, Obsidian never made a completely narratively linear game before. So that's something.
Lots and lots of ifs.
Seriously, no offense. But, you're assuming and somehow treat that assumption already as a fact for yourself.