Years ago, I used to do it like you. I imported everything manually into a standalone addressbook (I probably have several threads about it here) and then would periodically update it and export it to my phones and Outlook.
-superboyac
For me the manual bit is a singular event, I'm not going to signup to do shit periodically...that's the computer's job.
But this is where I'm getting a bit confused. It sounds like you configured connectors to live pull all of the contact info into the Exchange system. So that if you add/update a contact in FaceBook/Linked in/Gmail after the fact it will still (via the connector) share the new/updated info with all devices connected to Exchange's contact list. That would be fraught with turmoil as you say the Business Battle rages on.
My typical deployment is to centralize data scattered everywhere onto a single system, import all of the info into that system, and then to use it exclusively going forward. This way any and every thing that connects to it can/will get the same information set.
Do you actually need live sharing interactively between (FaceBook/Gmail/Linked in/Etc.) systems on an ongoing basis? Or do you just want/need a singular clean merger of all the contact info into a single contiguous block once so you can at all points work from there going forward?