Holy crap, your post went so far over my head haha.
Yes, the guts of a HDD enclosure should be totally fine with being used on a DVD drive. That SATA interface doesn't care at all.
It also sounds like you have an additional power source with your enclosure, which is good - you'll need it. Some enclosures just run off USB power but that won't be enough to spin up a DVD.
I've tried to find like a ready made solution for some external 5.25" drives, but havn't found anything. I basically just open up my case, plug it in with the panel off, and use it ghetto like that until i'm done.