As far as "pippim.com" coming soon goes, "pippim.github.io" will be coming sooner as I spent last weekend and this weekend working on it. pippim.com was developed in Google Sites and pippim.github.io was developed in Github Pages which is a more programmer friendly IMO.
aplay should be the default since alsa is always used for sound, by default it uses wav option. Other supported format are unusual and need -t flag: -t, --file-type TYPE File type (voc, wav, raw or au)
mpv as a CLI option
mpv is an audio/video player, it can play so many formats. I think that you can add some PA or pipewire with PA check, if there isn't MT can use mpv instead. or just the latter
when using pipewire you use PA commands/apps like pactl , pavucontrol etc.
It sounds like the easiest solution would just let the user pick the program to play sounds. In the short term the user just has to change paplay in the bash script to whatever they want to use.