RE: Throttle to Rudder Rate mix
No, it's pretty much stuck as a linear adjustment of rate as you can't (or I can't) assign a channel or virtual channel to the fine tune of the mixing rate. I can only assign a hardware input.
On the 14MZ the Rud-Rud mix works, and I didn't have to mix it to an AUX.
Having never owned a 9ZAP, it seems like it would b a really nifty thing to have, but I suppose in their wisdom Futaba dropped it thinking conditions and delays between conditions would more than cover it. I've never used delays between conditions as I experienced some weird servo twitches last time I tried setting delays (many software updates ago), maybe it's sorted now??