Hi. I think I have some answers, but more general than particular.
1) Yes. With Linux anything is possible
2) I don't quite understand your question. Why would you want the filesystem be mounted anytime an user wants to access it? Wouldn't it be more easy to just mount it once and to let (specific) users to access it? In this case, you need Samba..
3) Well, I don't know anything about 'shortcuts' in the desktop environment you use, but the universal way is to make a shell script like this:
exec "the program you want"
The key here is "cd". It changes the current working directory for the current context(this script), meaning the program will start with this new working directory.
4) But if 100 users want to access the same filesystem? It would be too costly on the processor....
Hope solves something..