I can’t answer many of the questions here, but I can help a little with two:

If you’re worried about noise, don’t get ironwolf drives. I just did and they’re noisy af. I brought some sound absorbing foam to put around the place where I keep my NAS, because they’re so much louder than I expected.

Don’t open up a port in your network.
Use something like tailscale to connect your devices to your home network, or rent an VPS to run a secure tunnel using pangolin (you’ll need to look into bandwidth limits).