G'day Mate,
Flaperon mixing is a mixture of 2 words flap & aileron, hence flaperon, this is where you have 2 servos, or more, controlling your ailerons, one for each side, you would set up flaperon mixing so that, you don't need a "Y" lead, then you can use the ailerons as normal, &/or use the ailerons as flaps for landing & take off, & retain aileron control.
Where you mix elevators & flaps, it is just that, an elevator to flap mix. But to do that you must have 2 servos, for your ailerons, otherwise, it won't work, because with one aileron servo, it can only make one aileron go up & the other must go down.
I hope that is clear, & I don't know if you plane has 2 aileron servos or just one in the middle of the wing.