How many characters/plot twist/locations/equipments.... Generally it does depend on the deck your using and your strategy. It also depends on if your team has a character tutor, resource replacement, KO pile replay and so on.
A Common Enemy deck might run 28 characters since it has "Boris" to fetch a plot twist, namely "Signal Flare" or "Faces Of Doom" to go fetch characters if needed. Common Enemy also has drawability with "Common Enemy".
A Titans Deck has "Optitron" to fetch characters, and "Garth" to replay plot twists and fetch characters from the KO Pile. Combine that with "Argus" for Drawability and "Tamaran" to toss cards in the KO Pile and you have a pretty go chance of hitting your character with only 28-29.
A Big Brotherhood deck will usually run about 40 characters because it doesn't have a character tutor or any cards to help it cycle through deck. Plus, a Big Brotherhood generally runs the "Lost City"/"Avalon" combo and require you to have a crap load of characters to discard for it.
So, you see it depends on the type of deck your going for and the team options.
As for a
Jinzo in VS, there really isn't that one character that every deck runs. Generally every team has that one character that is affiliated with the team that should be in no matter what, kinda like "Garth" should always be in a Titans deck.