Hey! As I wrote both guides I'd figure I'd chime in. I might be repeating info others have said but so be it.
I got to the part in this guide where it starts to talk about modding and and how WAMP was something I needed to use to install a web server for windows.
You don't actually need to worry about this at all if everyone who is playing has the mod downloaded and installed already.
Do I need WAMP and FastDL for this or could I just ignore that and follow the guide on how to load MP & ZM custom maps and mods guide instead?
If players connecting do not have the mod, then FastDL is required.
And how could I use it for this use case of running a custom modded zombies server (Links to guides, or just giving me a bit of an explination would be much appreciated!)
WAMP is the web server where the game looks for to serve your mods to connecting players to. I cannot give any guides as I do not use WAMP for my web server.
Is there any more important details that I should probably know about for dedicated servers like I saw in a thread pinned How to configure IW4MAdmin for Pluto T4 would that be of any use or help to me at all and how would I go about setting it up correctly?
IW4MAdmin is useful for kicking/banning players, but currently does not support ZM so I guess wait till that comes out then take a look if you wish to set it up, it is not a requirement by any means.
Hope this helped:)