One problem title you mentioned; Lunar. Is that Lunar: The Silver Star or Eternal Blue
Lunar: The Silver Star
Lunar: Eternal Blue
I would look for (and maybe request) redumps of whatever you need just to have a verified good source to start with. Warrior has some Sega CD redump shares here in the forums...not sure how many and maybe most of them are NTSC-J, but it doesn't hurt to request stuff.
Relevant request thread if you need to use it: