I can answer to some of your questions…
-
why HA on Synology and not on your PC? If nothing else, Syno runs 24/7 anyway and it has HDD mirroring, so i one of your HDD’s die you won’t loose anything.
-
You can set up remote acces via your synology’s domain → go to reverse proxy for that. No need for any DuckDNS. I explained procedure on my site. And don’t forget port forwarding in your router (explained at the beginning of my page). So, let’s say that now you already set up Synology DDNS address as https://yourname.synology.me. So, HA will be available at: https://home.yourname.synology.me.
-
you can set up different users with different access inside your HA installation. All users will access HA via syno’s reverse proxy address.