You can find the FIM CM documentation in the Certificate Management under the Forefront Identity Manager 2010 section on the TechNet Library.
At this time FIM CM does not support multiple forest scenarios.
The FIM FAQ document can be found on the TechNet Wiki under FIM FAQ Collection.
No, not at this time.
Yes, as of FIM 2010 Update 1 (build 4.0.3531.2).
No and testing for this platform is not anticipated.
CNG templates are not supported by FIM CM 2010.
Upgrading from CLM to FIM CM is not supported because CLM Feature Pack (FP1) is supported only on 32-bit platforms and FIM CM is only supported on 64-bit platforms. You can export the CLM 2007 database and re-use it in a new FIM CM deployment.