Jon said:
Seems like I need to persuade someone to drop test the fusion knot and the triple bowline in the configurations mentioned above.
To create a Y-hang with an integrated clip-in loop, I like the triple bowline best.
Finish it with a Yosemite tie-off, so that the clip-in loop loads correctly.
I don't know whether this knot is subject to the same issue as the bowline on the bight, where clipping just one of the Y loops could lead to the caver travelling rapidly back down the pitch. But since you're providing a convenient central clip-in loop, it seems unlikely that anyone would do that.
This knot is a little more fiddly to tie and adjust than more conventional options, but a lot less fiddly than the BFK (which also uses at least a mile of rope).
(I suppose in principle you could make a "triple fusion" instead of a triple bowline, but now I'm really veering into uncharted waters...)