Exchange Full Administrator at organization Level and Local 
machine Administrator Permissions

you need Schema Admin, Domain Admin and Enterprise Admin Permission.

For Installing the Ex server First time in an organization
The System Administrator must Member of 
1) Schema Admin
2) Domain Admin
3) Enterprise Admin Group

Depends if Forestprep and Domainprep have been already been 
run. If they have then you don't need Schema/Enterprise 
Admin rights, in this case answer #1 above is correct. In a 
large company this would most likely have already been done 
by someone in the Directory Services team.