Topic: Fireface 400 using adat and s/pdif

Hello, I just upgraded my equipment and now have a adi-8 and a fireface 400.  With my previous equipment I only used analogue i/o.
Now I want to go digital.   And have the ADI en FF connected by ADAT so I will get 8 digital channels in/out.
But beside that I have two pieces of outboard equipment  (compressor and equalizer) who also have digital in/outs by means of S/PDIF or AES.

I want to use them all at the same time.  So my first question before i buy a lot of cables is,  can both digital outputs on the FF 400 (adat and spdif coax) be used at the same time?
(i want to record thru the adi-8 - adat -> ff 400 -> daw,  a clean track.  I route the clean track to the FF s/pdif out to the outboard equipment and record the processed s/pdif in channel on a seperate track)

second quetion is not so much a rme question but more general on s/pdif,  can i built a chain with it,  so the s/pdif out of the FF goes to the compressor s/pdif IN, the compressor s/pdif OUT goes to the eq s/pdif IN and finally the eq s/pdif OUT goes to the FF s/pdif IN.

and which piece will be the best to use as a master clock?

I will be very happy if someone could say yes, it can be done, go buy the toslink and rca cables!

thanks beforehand
ab