Specifically addressing the word "DMZ", please read this thread for a bit of a discussion about trying to disambiguate the term. It is often used in marketing material or in ISP/consumer grade routers, but is typically not the best approach for exposing a host to the internet.
It would be best if you described your actual goal in plan language (rather than code) as to how those hosts should be exposed to the internet and what access they have to the other devices on your network and vice versa.
That said:
- if your goal is to expose ports 80 and 443 from a given host to the internet, you only need port forwarding.
- If you want to also isolate those hosts from your main network, you'll setup a separate subnet for those devices (using DSA syntax). You can actually start with the guest network tutorial (which creates an isolated guest wifi network; a few minor tweaks gets it to work on ethernet). The port forwarding would still apply here, except forwarded to a different destination zone.
Maybe... there are tons of examples on this forum -- search should surface many of those quickly. However, they may or may not be exactly setup to reach your own goals... so it might be easier for us to help you arrive there within this thread rather than pointing you to what might end up being partial or patchwork solutions.
I'm not sure what you're asking here, but no, don't try to directly apply settings from another device/situation to yours unless you can verify that it's the correct solution for you and that you can properly adapt for potential differences.
Why? I wouldn't recommend using snapshot in your situation... for this case, there's no benefit and there are plenty of downsides.