The NF.30 and FB.VI Mosquitoes would be very different. Down at AH combat altitudes the FB.VI would be faster due to low blown engines, ~320mph on the deck for the NF.30 and ~350mph on the deck for the FB.VI once the dampers are removed. And no, the NF.30 didn't use dampers, so no speed boost that way.
The A-26 was an attack aircraft. In AH it would be used as an attack aircraft and heavy fighter. The Mosquito FB.Mk VI was an attack aircraft and heavy fighter, and that is how it gets used in AH. If people are using it in the attack role it will often be very low, particularly after the new one is added and it is faster on the deck than any other twin piston aircraft down there. Mossies on fighter sorties tend to come in with altitude. They have the fuel to burn to setup however they like and they often use it.
If I were to compare the A-26 to any Mosquito it would be to the Mk VI and in that case I'd say the A-26 has a lot more potential for hitting ground targets while being much less of a threat air-to-air.