Concerning the holes from the missing compass/instruments...
I removed a broken bulkhead mounted compass
in the cockpit
on one of my boats, and had a similar hole left over. I bought a deck
access plate. They come in all sizes, and was a breeze to install. The ugly hole was replaced with a nice looking cover, with a removable plate as an added bonus. My kids
enjoyed this "hole" to below. They would pass things back and forth, or "peek" through it. It made for some added ventilation on hot days, or when cooking
. In general, it was a super low cost solution that turned out great.
They might be called access plates, or deck ports
, or something similar. They come in a variety of sizes, most likely one to fit your hole exactly.