That depends on how many users are in the channels. which also means, the more users, the more commands the bot can take without lagging.
I think in my opinion, 2 maybe 3 bots should be OK. it's not that much bandwidth, it's just a fre bytes per !trigger.
As for the trivia 24/7, that depends on the users playing at the same time as well. but yeah, I think 2 or 3 bots should be OK I suppose.
That question is kinda tricky if you know what I mean
I would test it with 1 to begin with..
Then add the 2nd.. see if it's lagging, and then load up some more..
Play with it, tell us what happens, would be interesting if you share that
It's always fun to share your experience!