I would say this is a very, very, long shot... but I do not want to discourage you, so here are my humble two cents:
* You will probably need to understand assembler, because you are not going to have access to the source code for the current firmware, and you will need that to do lots of reverse-engineering.
* You will also need to be able program in C, so you can write your own code.
* But before you can do anything useful with that knowledge, you will need to figure out how to execute your own on code on the camera's processor; Canon cameras have a nice mechanism to boot a program from the card, you should probably try to figure out whether there is something similar for Leica.
* One good starting point are firmware updates, if there is one available for your camera, but you will have to figure out how to interpret the file yourself.
* Only after you have understood the internals of the current firmware you will be able to answer questions 1 and 2.
* As far as I know, electronic shutter requires dedicated hardware.