Hero Griffith

I put them in order. unlz is for sprites, YAPE is for data, Icon Ed is for Icons.

Easy, look in the Toolbox section. I recommend:

unlz.gba (Read tuts, or it will go wrong!)
YAPE
Icon Ed
Errm... There was a tool for that. Forgot it's name.

Yes, but that isn't adding, but replacing. There are tutorials.

The Documents and Tutorial Section. It has Tutorials (hence the name) that tell you (you can only add 25 at the moment (however, you cannot catch them, as they have no Pokedex entry, causing the game to crash), but some ASM hackers are working a way to add more!)

Right. No, I won't help. Reason: You have the skills, as does everybody. You need to just train them, and improve. If you know little about scripting, I suggest you improve that, as if you scripted, it is easier in the long run.

(About the Fakemon one, you need an actual storyline and features, do not leave it the same. If it is just telling people of them, don't post it. If it isn't, you need to post a storyline and features. BUT only stick to 1 hack at a time!)

Which game is that? (I see a lot of hacks nowadays)