Another game version is too much work for a one-person project now. The story is totally same as FEH, and you can read English name and description of skills here.
to hear the GBA instruments on pc:
http://ngmansion.webcrow.jp/wp/2016/10/14/dominoでfe音源を鳴らす/
to add custom instruments:
http://feuniverse.us/t/inserting-custom-sound-samples/1081
to insert it into GBA rom:
http://feuniverse.us/t/music-hacking-the-elf-method-no-sappy-2006/102
http://feuniverse.us/t/sappy-graphical-user-interface-gui-explained/1074
http://feuniverse.us/t/insert-music-using-event-assembler/1832
http://ngmansion.xyz/wiki/hackfe/index.php?cmd=read&page=解説%2FFEBuilderGBA%2FMusic_EN
Yeah, this game has lots of info for you to read to complete a chapter. If you don't understand them, it will be painful to clear a map without any missing event. And it will be more and more difficult.