Don't float test them if they are externally pipped, or they can drown. With quail eggs, its hard to see the pip sometimes, the shells are dark and the hole is tiny.
Honestly, I understand this is your first hatch, and its hard emotionally, but the less you mess with the eggs the better. Put them in the incubator, candle them once if possible -- but with button quail eggs they're so dark there isn't much of a point in trying to candle them, move them once at lockdown if necessary, and otherwise just leave them alone. Try not to open the incubator any more than necessary to perform basic maintenance. In lieu of candling, at the halfway point you can do the "sniff test" to see if you detect any rotten eggs, which should of course be removed.
16 days is the minimum -- most of my quail eggs don't hatch on the 16 day schedule. I generally find a batch of quail eggs, button or coturnix, will hatch over a roughly 3 to 4 day period. A few at first, most on the 2nd day of the hatch period, with some stragglers on the last couple of days.