Yes -- Seloy is obscure. But like the other words from the verse, it's also written on signs in the FOY park. BP didn't expect anyone to know Seloy -- but if they saw it in the park, and recognized it from the verse, they'd know they were in the right spot. The acrostic doesn't have to run the full length of the verse for it to be a deliberate confirmer.
Incidentally, I like at least one of your ideas a lot, actually -- the Boston/optometry one. It's a very close match to the image, and it ties in, in a clever (but clear) way to points in the verse.
On this one, I think your process is favoring obscurity over simplicity, way beyond what I believe BP intended here. Obviously I'm not the arbiter of that. But if there's any chance of digging up another casque, the FOY is the best possible shot that exists right now, and efforts would be better spent towards finding where, exactly, it is buried on that site.
















