The ones with the black plastic perimeters are not the bilge drain. The one in the very bottom with a painted perimeter is likely the bilge drain plug. You should see it is open on the inside of the bilge.
The painted hole higher up is the splashwell drain. It is above the waterline and should not be plugged.
The fitting with the white cap is likely a fish box/livewell filler. It would have a pump attached to it. The other two fittings are likely fish box/livewell drains or drains for storage compartments.
On another note. It looks like the boat is too far on the trailer. There looks (can be deceiving) to be a roller for the keel. It looks to be behind the transom, rather than under it.
