Welcome Golden Groudon!
HI! I've been lost 4 a while, but noticed you've were around here as I got back tonite. I wish I had these answers off the top of my head, but I'm not in tip top shape(sick-cough, cough), but I like to help anyone I can and say HI to new Pokemoners! You seem to know what you're doing so far, though. Especially those on LG! We're rare!
I think the Unowns do nothing really, and the altering cave is still a bit of a mystery, but I suggest the following. Check the walkthroughs on this site-they are really great, and they go over the islands well,(one is just on the islands I think)so try there first. Then, check the stuff in the Question and Answers,User Submitted Hints and Cheats,& Codes sections for BOTH LeafGreen and FireRed. Many of the answers you seek are already answered there as well. The FR areas and forums are much more active, so there's more stuff there than in this LG section. I know the Aurora code is all over the place, but I don't have AR and think you need to use Version 3.0 for it to work...you'll find it here somewhere.
Well, hope you enjoy this site and finds this stuff helpful. Wish I could do more-but I'm also playing B/R/Y and Silver and LG and FR, so I'm all over the place but not that far in LG/FR just yet and there is more to life than games, right? Too bad,huh? LOL
I got all the Pokemon a person could dream of, and still working on more. If you need to know the truth, seek it out here, as I am obsessed with answering all the questions I can as best I can. I can verify Event Pokemon, too! My collection keeps growing!