..otherwise .. hell yes
I have a PCM 90 wired' like that. IIRC (don't use it much lately) the FX will want to be set to follow the digi input for it's clock source.
Oh I've got a few fx like Roland srv-330, lexicon mpx-1 and yamaha spx2000 I wanna try out. That would go into my behringer ada8200 and be connected by optical cable into the apollo twin. Not sure if my logic holds up when I get around to it. Basically using the ada8200 like a patchbay.