Is the CPBM 2.3.1 Patch C capable to operate with CCP 4.5?

Yes. This info is available at http://support.citrix.com/proddocs/topic/cpbm-23-map/ccpb-ccp-conn-wrapper-con.html.

Is the CPBM 2.3.1 Patch C capable to operate with CCP 4.5?

I am not very familiar with CPSM but I encourage to look up the CPSM documentation for this info.

Which order do I have to follow not to get into troubles with compatibility issues?

I would use the following order:

-- CPSM should be here but double check doc or with CPSM support ---

1. CCP 4.3 -> CCP 4.5

2. XS 6.2 -> XS 6.5

3. CPBM is already running the latest

Note that I have limited familiarity with CPSM but I presume it most likely should be the first component to be upgraded. I encourage to either look up the documentation or raise a support ticket with CPSM to get this information.