I have owned all of this stuff at one time or another. My advice put the SX-1 away for now and try the CD32 FMV all by itself. Once you have this working CAREFULLY add back the extras. The stock CD32 PS might not be up to the task. You can also overload and pop the small "Zero Ohm" resistor on the CD32 motherboard and render it dead if you are not careful. I remember the pass-through on my SX-1 was finicky at best 20 years ago. Good Luck!
BTW I sold my FMV off years ago. Should you decide to give up on yours, and it still has the rear plastic cover, please send me a PM. I might just make you a sweet trade offer or buy it from you.