That's not the sort of thing I usually do, so I wouldn't be the best person to advise you on the speed requirements of specific convolution solutions whilst decoding bluray.
I would expect an internal SATA bluray drive to have lower CPU requirements than a USB device, but on a modern CPU I doubt it will be a critical difference. But I always rip to MKV. I have no interest in playing with disc menus and watching forced trailers and copyright warnings: I just want to get to my content. That's what I would recommend, but I know some people like the menus and extras, etc. Ripping eliminates any concerns about spin-up delay, noise, retries, glitches etc associated with live playback as well.
Perhaps someone else will come along with experience more aligned with your specific use case... There are several people here who do convolution with home theater, so one of them might see this.