So where does fascia fit in above and beyond this?
Frankly, I don't see any point in discussing what is a best a hypothetical topic with most of the people on this forum. We do extended discussions on this stuff on the QiJin forum (and previous forums), but since most people can't even do simple jin, the fascia, qi/ki, muscle-tendon theory/channels, acupuncture relationships, etc., are probably just exercises in typing on this forum.
Let me note again that one of my cautions is that this stuff has levels of skills and often people think that the level they're at is all there is to know so they use the buzzwords indiscriminately. I'd suggest that people take every expert's opinion and every "epiphany" with a grain of salt. In my perspective, the most correct approach to Aikido is actually going to be the soft approach that Tohei espouses or a related version. The harder approaches do indeed use "ki" and "kokyu-power", but O-Sensei apparently preferred the very soft approach (and he says that clearly), so anyone starting out on this road needs to bear that in mind, IMO. And needs to explore the why's before too much is committed on yet another tangential path, even if it's somewhat more informed than just normal strength.