Does Aerodactyl GX's "Primal Winds" Ability add {*} to the cost of an attack used by Mewtwo & Mew GX's "Perfection" Ability if it tries to use an attack from a non-Basic Pokemon?
Yes, it does. Mewtwo & Mew GX is still a Basic Pokemon; it doesn't matter whether Perfection uses the attack from a non-Basic Pokemon or not.
Source: TPCi Rules Team (2020-03-12)