To be hosted where? If it's for the Nintendo 3DS e-shop, you won't be able to post it, since your program has a dependency on SmileBASIC. If it's for someone's virtual/emulated "OS", ask that person what format you need to provide.
You shouldn't need one. If your program requires multiple files, place them all in the same folder. Then at the program upload menu, select that folder instead of a file within it. The entire folder will be uploaded as one.
Tip: Don't program the title screen first. I've lost count of how many progams end up being just a title screen. Break the program down into chunks of code that perform functions. If you were designing a car would you start with the little chrome name badge? Work on the engine, transmission, differential, brakes, suspension, steering, windshield wipers, horn, seat belts, etc.
This screenshot shows what it looks like when run twice.
Only upper case A through Z are encoded / decoded. All other characters pass through unchanged. To decode, use the negative of the offset that was entered during encoding. e.g. if you encode with 7, use -7 to decode.
The required args are listed in the built-in help.
However. Playing back at 16-bit is a different story.
Allowing us to use sound & picture files from external sources would be a big help.
The sound data is held in an array. It's a simple task to display it on the screen to allow editing, and to save it to a file that can be read back and played later. I don't understand what else you need.