Hi Jonathan,
I’m not sure to understand precisely your expectations about the sound system you’d like. There are 2 different questions in your message:
First, I would advise you to buy a set of active speakers since you will use them as a monitoring system. An active speaker provides more precision, more neutral sound, etc…
Concerning your studio architecture, you only have 8 discrete analog outputs on your RME. That means that you will never be able to get 16 discrete channels on your sound system, so I don’t really understand why you want to use a “coupled” system in which each speaker is doubled, and each active/passive couple fed with the same signal. Moreover, in case you use a coupled setup (1 with an included 1 channel amp, the other with a 2 channels external amp able to feed 2 passive speakers), you will have big differences in the sound quality between the 2 kinds of speakers, and thus a non-homogeneous sound space.
My advice would be to buy a 8 active speakers system.
Kind regards.
Julien ALEONARD. Ircam Sound Engineer.