JonnyBGood, I think you're confused on a few things
First, a BNC adapter would just be a straight metal connector. It doesn't have to be "meant" or "built" for analog or digital. Metal is metal (although some metals conduct better) and it will pass whatever signal through that you feed it.
USB cables are highly controversial. Personally, I wouldn't use the cheapest one I could find but I wouldn't go out and buy a $100 one either. I have a Belkin Gold that I got many years ago, it's got gold plated pins for better wear (which is why it's lasted this long) and is a shielded USB 2.0 compliant cable. Sure it could be "better" in some people's eyes but it transfers data and I don't feel it's holding me back. There's plenty of other things in your chain to spend $$ on before going "crazy" with USB cables. I mean, analog cables matter more than USB ones, I think everybody will agree on that.
Finally, the Tenor 7022L would be your best bet from your computer. But, the "is better than OPA627 from coax" doesn't really make sense. The opamps are used no matter what input you use. Personally, I would avoid using onboard audio, even if it's digital output. The Tenor chip is 24/96 and driverless. Simple and works.
For your P.S., Head-Fi is for a bunch of topics, there's threads for computer audio and speakers. With that said, you'll primarily find headphone related items. This sub forum though is "Dedicated Source Components" which is exactly what the D2 is.