mBrane:that's why i wrote,"customised Y pwm splitter". - Y splitter that regulates simultaneously both pwm pumps from one pwm connector, with rpm wire only from one pump (so far like all the Y splitters) + rpm wire from 2nd pump instead of being cut goes to _separate_ 3-pin connector that i can connect to another channel, not for regulating, just to get rpm readings from 2nd pump too.
So as to your first question - i still haven't got my AA5, so i cannot say for sure, but imho pwm pump shouldn't be any different from pwm fans, and i should be able to regulate them both from that single pwm connector using mentioned Y splitter.