Hi Mike:
Same problem here. It seems you know what to do with the edges. See my pics. I sanded/grinded down to good material. Be sure use a respirator, safety googles, and long sleeves. Fiberglass dust is nasty, itchy, and you don't want to breathe it in. Then I used Epoxy mixed with cabosil (silica) and cut pieces of fiberglass cloth to reinforce. I also used straight edge wood clamped to the edges, the wood was covered with clear packing tape, so that I can release it easily once the epoxy cured.
Now for your topside, non-skid, I think recreating the pattern may be too time consuming for a DIY. There are youtube tutorials on how to make a mold of the pattern.
If your topside of the hatch is weak, then I would epoxy or fiberglass a layer of cloth over the entire topside. First you will need to sand the old pattern down a bit for the epoxy or resin to bite into. My hatch is strong so I will skip this step. My non-skid pattern is non existent, it is a 1988 boat and the pattern has plain worn down.
I will roll or paint a layer of epoxy over the topside and sprinkle either some sand or store bought non-skid. Once the epoxy cures, I will put a layer of primer and paint over the non-skid.
Two ways to do this, either recreate the pattern you have there or recreate a new non-skid.
Hope this helps. I am going through this now too so please let me know if you have any ideas to share with me also.
~Nick