All 3 of them (Andre, Fed, Nole) have their selling points for AO GOAT imo. For Andre, it's winning three of them in his late 20's and early 30's. For Fed, he has titles on both rebound ace and plexicushion. Nole has 3 in a row.
Probably I'd give the edge to Nole. Obviously if he wins another he'll be undisputed AO GOAT.