Whether they're alive or not and the date of V is besides the point. The III era (III, Vice City, San Andreas, Liberty City Stories and Vice City Stories) and the HD era (IV + LATD + BOGT, V) are two different universes. The developers have said that the old characters (i.e. Claude/Tommy/CJ/Vic) are myths and tall stories in the HD era.
I'm sure there will be characters like Sweet etc in the game, but not the same characters or stories.
That is pretty much the answer right there plus San Andreas was to have taken place in 1992 which is why they play off such things such as the LA riots and Boyz N the Hood. GTA V looks to be taking place close to present time.
This game will be a financial success no doubt about it. I'd be a dumbass too say It wont. However in my eye's as a HUGE grand theft auto fan. This game will always go down in history as the game that killed the series.
Now I know Vice city was a Scarface rip off. I get it gta is a cliché video game series. San andreas caplized on the popularity of hip hop when it came out. However those where good things to copy, Things that could work in a video game.
Gta V is nothing more than a rip off of every American teen mode ever made... You have the Wife who looks after the house, Spends the money and complains her husbands never home. The daughter is a slut and Michael will have to '' scare the boyfriend'' to defend his daughters honor . The son is a fat dumb Ass ''gangsta wannabe'' and Michael is the stereotypical husband who looks after his family but is never home.
Throw in franklin a very poor mans Luis lopez along with trevor a guy who's supposed to be a white trash rapist who's biggest crime will be standard murder and setting houses on fire when nobody is home.........
The game's a piece of shit. Theirs not one decent character in the game
TLDR : gTA V = P.g wwe after watching the attitude era......