Skin-wise, the thing to know is that modified templates are marked by a red bullet. This means if they've been modified ever.
The 2015 attacks -- which we recently saw a recurrence of -- involved changes to files that didn't even necessarily show an edit. These files were includeCSS or includeJS in each skin's templates, and they look like the following chunk of text appended to the bottom of the file (image at bottom of email)
This should become a moot point with the IPB4 upgrade, but it's always possible that we'll see such things again.
IP.Blocks are the primary way I add stuff to the site. If there's an advertisement or an announcement block for example, that goes into a new or existing block. The blocks are dropped into the template (usually Global Templates > globalTemplate for a header, or Board Index Template > boardIndexTemplate for the sidebar) as {parse block = "blockname"}
Pre/Next Game Block right now depends on a PHP template called 'Game Data'.
SQL: In support > SQL toolbox you can run MySQL queries on any of the database tables. Obviously, a LOT can go wrong if you do this so be vewy vewy careful!
Member Management: For the most part, I don't think such things are worth it. I think we can make reasonable efforts to sniff out users without really diving deep and make sure we've sussed somebody out. If it's a question of a sock puppet I'll look up all used IPs as described in the wutthewut thread. You can click "learn more" on each of the IPs listed; it'll also show at a glance whether it was used for other registrations. Keep in mind the Verizon, T-Mobile, sprint, AT&T etc addresses -- referring to their mobile networks -- often get shared among users, and so do things like public IPs and university addresses.
Donor Button: The easy way to do this is to add someone to the following secondary groups: "Huskerboard Donor" and "Huskerboard Donor - {COLOR}". There's some template code that checks for these. It's in the userInfoPane template and it's tagged with a <!--@zoogs--> comment. Who knows how this will survive the board upgrade, if at all. I'm not too worried about it if it doesn't, but the code is there to save in case it works. Here's a paste bin:
https://pastebin.com/hZeqA0Sg
(One thing I haven't been great at is organizing everything, so this is a bit haphazard -- my apologies. I've often thought about how to make everything more modular/future-proof but never implemented it. IMO if it can't be easily done and maintained, it's not worth it going forward.)
Forums/Member Groups: I mostly never touched this stuff. I tried looking up Nexus just now and can't figure out why he's in any of the Mods lists.
The easiest way to permanently maintain a Recruiting Mod is to create a third Mods group derived from the Mods list, and so ever Recruiting Forum going forward will have that group as a Moderator. However, the even quicker way is to just add seaofred manually from the forums page -- you'd just have to do this every time there's a new forum. Hence it may just be easier to make him a full Mod after a little while, but of course he may not be interested in that.