Bekoha

Thank you for being a great poster! Incredible questions too, sincerely.

1. I don't think I actually remember the very first, but on the creation side most likely that would be messing with official editors that were distributed together with games. Warcraft 3 immediately comes to mind with how great and approachable its level editor was that even a kid could figure it out enough to be able to make what charitably can be called a map and get it to actually load in the game. If it's just installing mods that counts then it'd definitely be something from a magazine covermount disc, as those came absolutely loaded with maps and mods for practically every popular game at the time - Half-Life 1, Counter-Strike, Quake 3 Arena, its engine derivatives and especially Jedi Knight 2 and Jedi Academy, Max Paynes... Special shoutout to a disc that simultaneously had custom models for Half-Life 2 that replaced both the crowbar with a lightsaber complete with sounds and the gravity gun with "using Force", using those two together at the same time and playing Duel of the Fates in an external music player is a core memory for me, yeah. The first mod I actually still remember sharing online would be Team Fortress 2 reskins around late 2007 or early 2008, as I got into Garry's Mod around the same time, but there might've been something earlier and probably related to Sonic, as I was really big into SADX.
2. Ever since obtaining a pirated copy of Photoshop, I always enjoyed making silly little edits and "fanarts". For a lot of those, I tried to recreate the original logos and whatnot as closely as possible, which was complicated by the fact that a lot of fonts only cover Latin range, so to be able to use them for my edits, which at the time were primarily in Russian, I had to recreate needed missing Cyrillic letters out of bits and pieces of Latin ones, so that's where most of my font knowledge comes from.

Hopefully that wasn't too boring to read! Thanks for such a great ask.