Foxsos91

I don't know if it's been said or not, but for FreezyNinja, the RA_emulators have the tools included in them to make/get achievements. It sounds like SamuraiGoroh's already mapped most if not all of the needed addresses, but I haven't seen what they look like.
If you do need to find things, you usually do some logical processes-of-elimination in 'Memory Inspector' by guessing what is changing and WHEN it changes, then gradually eliminating the addresses don't have anything to do what you're looking for(hopefully) and change things in the game until you do filter out the ones you want. (For instance, you can usually find XY coordinates easily by staying in place, filter by , then walk left and filter by <(as long as map coordinates go down walking left) stay in place and filter by , walk right and filter by >, etc etc... usually you end up with the only address that changed the way you expected and then you can make a Code Note for it so it'll be easily accessible, as long as it's something you want.
After that, it's a human-matter of analyzing the whole layout of the game, picking out which parts are the MAIN things that you want to award points for, thinking of some interesting/clever/funny/etc things to give more character to the set(IF you're able to find them in memory anyway), make an achievement, then fill each achievement with 'Requirements' that watch for multiple addresses to have the desired value at the correct time(and possibly ResetIf it's NOT the right time so things don't pop at the wrong time).
It can be a lengthy process, especially for a huge game like an RPG, or possibly a game/system where values swap out repeatedly for no reason and making address-hunting difficult or make addresses unreliable if they change unexpectedly. Sometimes GBA can be finicky for that matter, but in some ways it's better than NES which makes its RAM become just about every value possible for a split second, which can cause some not-so-well-made(my early) achievements to immediately pop on start-up. But it can be fun.
As far as copy+paste goes, probably not a great idea. Potentially, you could load up the SNES game, grab the TXT file from your RACache, and rename it to the game-ID for the Local Achievements name, but it would mean all the addresses in the achievements would be wrong, so all of them would need to be tweaked. The GBA version may also behave completely different. The most it would do is at least create the skeletal-frame as far as text and descriptions go, but pretty much need to be fully reworked anyway. And typically you want to find something at least a little bit unique for the GBA version than just be the same thing as the SNES version. Some might even find it a problem if you took their text and re-used it as yours, who knows(maybe not, but you never know).
Anyway, as long as you open up Achievement Sets and click 'Local Achievements' you can make your own test-achievements without any problem, and could hopefully be a fun learning experience even if you don't do anything. Just read some tutorials and ask around in chat and you should be able to do something...as long as the memory plays fair and doesn't do stupid stuff.