Is DFS-R service required for Exchange 2010?

Hello,

I am new to this forum, so let me know if I have not posted at right place.

We have 3 DC running Server 2003, having schema version 30.

2 HUB/CAS and 2 MBX servers running Exchange 2010 SP1 with DAG.

On 1 MBX server, no FRS and DFS-R service is installed/running and no "AD Domain Service" role is installed. 

While on 2nd MBX server, below is there

1. FRS service in "disabled" state

2. DFS-R service in "running" state

3. AD Domain Service role is installed. Just role is installed, not promoted to DC

These 2 Exchange servers are NOT DC.

So want to know if;

1) FRS can be uninstalled?

2) DFS-R can be uninstalled?

3) AD Domain Service Role can be uninstalled?

4) Is there any requirement for this DFS-R and AD Domain service role on Exchange server?

Thanks for your help.