Yeah, I like that part of Japanese. Lots of homonyms. And names can be made up of whatever you want. Like you could make the name 光残 and it would sound the same, but if would be made of different kanji with different meanings that don't even have to be a real word since it's a name.
Yeah I don't like those much haha, but they're cool. If I do plan to change my name then I change my alt account AWsqaured (which I made by accident) and make this name Kouzan. Then I can have AWsquared when I want to change back and no one can steal it.
As for the origins of this name, it's a long story, but basically it's a name I've been using on websites since at least 2010. It's a combination of my initials (AW or Aaron Wolf) in real life and the math term"sqaured" or square number. This explains it a bit more. Fourth question I believe. As for Kouzan, it's a name of an OC for a fanfic I was gonna write several years back that I never got around to. Kouzan was based on me and my personally and I just got the name when I typed my name in a Japanese name generator, I got Kouzan Kurofuji.
(I see you changed your avatar to Espurr now which is funny.) Nah I'm not too big on numbers in a username. There is apparently a user named Treecko, but they haven't been active since 2006. http://www.pokecommunity.com/member.php?u=12299
I much rather change my name to a name I used on some other forums, Kouzan. Though I'm very much attached to this name so maybe not.