The last 3 USB drives you mention don't have the words M-Disc on the specs so I'm assuming they're not capable of M-Disc?
Since I'm getting a brand new computer, it'd be nice to have an internal blu-ray drive already included. I'd be interested in that LG BU20N you mentioned but it seems hard to find and it costs $419.34 on Amazon brand new. It only costs an extra $50 for the blu-ray drive on Dell's site. The problem is, I'm not sure if it's the same drive or if it's different, will it be M-Disc or BDXL compatible? The chat reps tell me different things, some say yes and some say no. They don't know the name of the brand. What I'll probably end up doing is buying it with their blu-ray drive included and see if it works. If not, then I'll considering the other external options.
I'm not familiar with enclosures. If I put that Pioneer BD209M inside an enclosure, will the enclosure accept the drive with SATA ports and then connect to the computer with a USB cable? Can you give me an example of an enclosure that would do this? It's also not clear whether that BD209M does M-Discs. Does it?