2nd question-Mid-Fi DVD/CDP Carousel + Good DAC = ????

Dwpc- If you're looking for convenience, the carousel is the way to go. If you're looking for the best sound quality, stay with a single disc transport or CDP. The "sound" of a transport system, whether it is internal as in a CDP or a dedicated CD reader in conjunction with isolation components, greatly contributes to the overall playback quality. Jitter, data errors, noise shared through cable ground connections will negatively affect the sound from the transport/DAC system. If "good enough" is what you're looking for, look into the carousels. If you're trying to get the best sound possible from your equipment, at least consider a dedicated transport/CDP for your serious listening. Just my .02

Frankly, a Sony 300 disk changer is probably a better transport than your old 1986 CD player. I have a 300 disk changed I have used as a jukebox for commercial recordings plugged into $3k+ DAC and it sounds great. Not as good as my great Audio Alchemy transport, but it is beter than some older CD players I have had in the past.