1 - you can use skype and let them watch only.
2 - they can all buy the software and you can share the project you are working on and you can do video conference with them via skype
3 - I can't conceive how this can be done without some sort of advanced programming since Iclone isn't created for that , there are programs that can do that though , but they are more complex than Iclone ... http://www.caligari.com/products/trueSpace/ts75/Brochure/solutions_collaboration.asp
my 2 cents, everything is possible, just maybe not exactly how you intended it , cheers :)
☯🐉
"To define Tao is to defile it" - Lao Tzu