Yeah. The yeasties will be munching away at the batch while the fast ferment is going on. The horse will have already bolted by the time you learn anything useful, if such a thing might happen from a fast ferment test in this situation - I'm dubious. We know it is bottled too early. Not sure what the value is.
Not being bottled so very early. Look at it this way - you've done the equivalent of over-priming by 8 times the usual amount. Not worth stuffing around with the risk of the recapping process, IMO.
Yeah. Or tip it. Don't think about letting it ferment out in the bottle. I wouldn't think about tipping it back into the fermenter but you could try it, I guess.
Yeah, flavour as well. I find that kit GBs aren't in their prime for months. You should not let these bottles sit around for months. I strongly suspect they couldn't survive that long anyway.
Yep.
Nope. Some people have a higher sensitivity to yeast though and there will be more in the GB so young.
I still see a real safety issue. Your call to make.