Welcome to LQ!
Yeah, you are really ambitious about your quest. There are solutions for your requirements. But don't expect them to act 100% like a Microsoft products. Since Microsofts development model and most of the technologies they use are not so open ans not really adhering to standards (even the LDAP they use for AD is not pure LDAP) this is quite natural. This is simply how it just works.
Anyway check this thread
also. It includes some links.
For exchange server like functionality, I heard there's a product from Novell - Open Exchange Server
There's another product called Open Xchange
. Both seems to be commercial. Open Xchange has a free (open source) version, but I didn't check about Novell.
Check these also. OpenGroupware
. Both are open source.
These are not the exact things you asked for. But those will help you as a starting point. If you can play a little around with Linux, you'll have fair solutions. Whenever you have problems, LQ is here to help.
Note: I wonder, if you are planning to go ahead with your plan it might be better start threads in "Linux - Enterprise" forum when you come across problems.