sealing through-hull screws from keel-guard removal

I have removed the keel guard on my 15' Pathfinder tunnel skiff that I am replacing the stringers on. The keel guard had 20 thru-hull screws that I have removed, as you can see in the photos. I have the stringers up under the bow removed and grinded away and prepped for re-build. You can see where the small holes from the screws are visible. What would be the best way to seal these up? In the photos you see on the bottom of the hull some of the gel coat has cracked/chipped away down to the fiberglass where the screws were placed. I am assuming grind away the gel coat, seal the holes with 5200, and patch chipped areas with epoxy resin. Is this the best way to go about this? What will I use to finish the epoxy patches, as I understand gel-coat doesn't work too well over epoxy? Thank you all in advance for your guidance.

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