Unfortunately, google removed feature which we used for blue cursor in android 6 or 7. Just now is not finished new console mode, so unfortunately, you really must connect mouse…
Magic dosbox supports two midi via soundfonts and mt32 (munt library). If you use sound font then you can switch to another of the sound is not good. I think sound fonta were discussed here on forum in the past. I use GeneralUser_GS_SoftSynth_v144.sf2
There is no automated mechanism for sharing mgc files. But we have forum section “mgc file sharing”, people share their layouts there, I will be very happy for any new:) You must upload ngc file to some file sharing server and put download link in your post. But you can send mgc file on my email and I can upload it to ftp of this web and will be there forever.