That is quite interesting to say the least, the story behind it is really cool though. Now for the flavors I'd say that is all from adjuncts. Maybe it was aged for a time with oak, leading the harsher flavor and that whiskey like hint you got. Aging it won't make it taste stronger, in fact it should mellow any alcohol burn it could have quite a bit, especially over 20 years. I've never made a plum wine, so I may be wrong, but just going on my bit of experience with country wines.
Meads: Hababero and Sarrano Capiscumel, Show Mead possibly getting split and flavored, and 12 gallons of Bochet Deliciousness
Ciders:3 Ciders with differing additives TBD, Strawberry/Apple Cider
Wine: Black Cherry Vanilla Port