Check under all the rubber grill mounts. You can try using a rod that fits in, holding with fingernail, wiggling out. Can be annoying. Maybe grab with pliers. Some methods will damage the rubber more than others.
Every 4 around the woofers is likely a screw underneath. They likely fasten both the baffle and the woofers, so lay baffle face up. Also likely under the ones at top and bottom of baffle.
If it's hot glued then you'd have to try and heat the whole thing to make it softer. Though you normally see that more in cheaper mini system speakers, these are likely screwed with foam gasket.
The tweeter will be screwed into the baffle from the rear. Beware it will be just the magnet and diaphragm as the faceplate waveguide is part of the baffle.