Not sure why the RCA things is a problem with active monitors...just get a conversion cable.
Do you know if the amp for the passive monitors takes RCA?
Here's the thing...with a passive system, you have two sets of components that need to match up well...with an active system, it's already been matched up for you...not to mention, you don't need a place for the amp, it's built into the monitor enclosure.
I have one active pair and two passive systems, which are a bit older. But if I had to buy new, unless it was some VERY high-end, esoteric passive system coupled with similar type amps...I would get active monitors again.
AFA monitor control...there are a bunch of products out there...it comes down to what you need to connect to it AFA how much flexibility it must have.