To help answer some questions here -
The website launched with the DB isn't needed, and my config tool helps manage accounts a bit better. This also saves from having to run Apache, and can manage GM levels easier for accounts
You CAN run this server to be public just like any other Wow server. My config tool does indeed help with this in setting the IP (updates the config/client/DB entries to match), as well as keeping the 7.3.5 client build easily set to whatever you're running. It connects to a realm with the same build only, which is why it needs specified. Set the IP to your external/live IP, open/forward router ports to the LAN IP of the server, and should be good to go.
Like with any servers, minimal clients are horrid. Good luck

Any missing options in the world config should get added by my tool as well.
Solocraft is nice, but FlexCraft options break this down into multiple categories with a lot more customization/control. There are no magic settings. Check the SPP discord for more info.
The world/hotfixes is indeed semi-locked, the reasons are listed in the SPP discord. The battlepay can be edited there, but too many changes can break and make the server crash on startup. You're on your own if you do.
KTBL Gaming has a couple videos to help with install if needed, can search on youtube
If you run this on an HDD rather than SSD, you'll suffer load times. If you run on less than 8gb FREE memory, you'll suffer load times. The server may say it's ready, but can take a while to be able to login. This is a very large repack, and may take a bit to settle down after startup to respond to logins. Upgrade if it's an issue.
Mage tower (wasn't available for all during Legion) and Garrisons/Class Halls do work, but may require some pre-reqs. Visit the SPP discord for more info, and also some items at gmisland (.tele gmisland)
No, there is no coin miner in this. Conan had added one in some earlier repacks I believe, and was a pretty retarded move.
This repack is STILL having updates sent out for it, and will continue to do so for quite some time.
Most old content "works", and I've been helping zones slowly get up to par with actually being cleaned up with phasing, quest fixes, scripting, etc. There's probably 10 years worth of work if I was doing alone, if not more. Hopefully won't take that long

I likely will not see replies, or may be a few more years before I do

The SPP discord should have answers for most things. Just use the search, it is your friend.