If the /storage/roms/amiga directory is empty Amiga won't be listed in ES. So place your games in there and make sure the file extension is one of these: .fs-uae .adf .adz .zip
ahh too used to there being the start.sh for amiberry in retropie which kinda is why i guess even after a fresh Setup and after installing the emulator it was showing! thanks for the clarification so far i dont see a reason to switch back to it from this build. espcially since they dont plan to touch Kodi 18 untill its a Stable (non alpha or beta) (coulda been nice if they did just under an experimental listing in thier setup script:/ ohh well :3 being a full OS Build off raspbian it has always felt a bit more bloated.