Pacino is now 74, the age Michael Corleone would be in 1994.

Garcia in recent photos has looked a lot like ... uhm... Francis Ford Coppola, with beard, etc etc.

Talia Shire is 68 and seems semi-retired, although she does attend Hollywood functions and could probably make an appearance as a late-70s Connie.

Franc D'Ambrosio has never appeared in another movie, although he has done a lot of opera and stage work, so theoretically he could play Anthony -- unless Paramount wanted to recast with a bigger name.

I think ANY Godfather IV would almost have to include a couple of Vito's other grandchildren: Santino Jr., Sonny's legitimate son, and Connie's son Michael Francis Rizzi-Corleone, the baby shown being baptized during the mob massacre at the end of GF I in 1955.

Santino could be explained as having left the Corleone family orbit and moved away to Florida to pursue "legitimate" business during GF III.

Michael Francis could be shown as the result of Connie's neglectful parenting in GF II -- it was commented at the time (1959-60) that her older son, Victor, had already been involved in crime, so it would be no big stretch to explain that Michael Francis had been in trouble with the law much of his youth and was off in prison in 1979-80 when GF III took place.

IMO, over the years and multiple divorces, Connie would have dumped the surname Rizzi and any other of her husband's names, and returned to the use of her maiden name -- she always considered herself a Corleone above anything else -- and probably changed her sons' names too.

So by the mid-1990s, Michael Francis Rizzi-Corleone would be about 40 -- an age for which Robert Downey, Jr., 49, could easily pass.

Downey certainly resembles Pacino enough it would be no stretch to sell him as his nephew (or Connie's son).

The theme of GF IV could be Vincent's tenure as Don running into trouble due to bad decisions such as getting involved in narcotics trade, and Santino Jr. and Michael Francis competing to take over after his downfall.

Anthony could return as the "Tom Hagen" figure serving as the legal brains of the family -- his loyalty would be crucial to decide which cousin would take control.

So you would have Sonny's illegitmate son leading the family into disaster, with Sonny's legitimate son and Connie's son competing to replace him -- with Michael's son advising them all.