Outside of R2/3PO, (who are droids & don't age), is there a single character that stretches out that "life point" over "years" ?
You say things like Wedge but when do they ever let 22 YO Wedge also be 55 YO Wedge?
I think if New Republic ever shows up as a faction, we are far more likely to see them introduce totally new versions of those characters.
PS.
I did think of 1 while I was typing this. Moff Gideon. They gave him Empire since Remnant wasn't fully fleshed out yet but in turn have given everyone who isn't a "trooper" either Empire OR Remnant since then.
Even so, I don't think it's likely.
Far too much a chance they fork up kits somehow.
Look at "Specters", they refuse to use Phoenix on the new characters because its going to make Coding entirely too hard.