Yes all 4 clusters can use the same CP and yes you need to upgrade CP server to 6.1 - see extract from VCS install guides:
See extracts below:
6.0:
CP server requirements
VCS 6.0 clusters (application clusters) support coordination point servers (CP
servers) which are hosted on the following VCS and SFHA versions:
- CS 6.0, 5.1SP1, or 5.1 single-node cluster
Single-node VCS clusters with VCS 5.1 SP1 RP1 and later or VCS 6.0 and later that hosts CP server does not require LLT and GAB to be configured.
- SFHA 6.0, 5.1SP1, or 5.1 cluster
Warning: Before you upgrade 5.1 CP server nodes to use VCS or SFHA 6.0, you
must upgrade all the application clusters that use this CP server to version 6.0.
Application clusters at version 5.1 cannot communicate with CP server that runs
VCS or SFHA 5.1 SP1 or later.
6.1:
CP server requirements
VCS 6.1 clusters (application clusters) support coordination point servers (CP
servers) which are hosted on the following VCS and SFHA versions:
- VCS 6.1 single-node cluster
Single-node VCS clusters that hosts CP server requires you to configure LL and GAB.
- SFHA 6.1 cluster
Warning: If you want to upgrade application clusters that use CP server based
fencing to 6.1, make sure that you first upgrade VCS or SFHA on the CP server
systems. Then, upgrade all application clusters to version 6.1. However, note that
the CP server upgraded to 6.1 can support application clusters on 6.1 (HTTPS-based
communication) and application clusters prior to 6.1 (IPM-based communication).
When you configure the CP server, the installer asks the VIPs for HTTPS-based
communication (if the clients are on release version 6.1) or VIPs for IPM-based
communication (if the clients are on a release version prior to 6.1).
6.2
CP server requirements
VCS 6.2 clusters (application clusters) support coordination point servers (CP
servers) that are hosted on the following VCS and SFHA versions:
- VCS 6.1 or later single-node cluster
- SFHA 6.1 or later cluster
Upgrade considerations for CP servers
- Upgrade VCS or SFHA on CP servers to version 6.2 if the current release version is prior to version 6.1.
- You do not need to upgrade CP servers to version 6.2 if the release version is 6.1.
So in summary the above means:
6.0 – Application cluster can be higher – i.e – VCS 6.0 can communicate with CPS 5.1 (but NOT vice versa so CPS 6.0 can NOT communicate with VCS 5.1
6.1 – CPS can be higher i.e – CPS 6.1 can communicate with VCS 6.0 (NOT vice versa)
6.2 – CPS can be higher i.e – CPS 6.2 can communicate with VCS 6.1
So you need to upgrade CP server to 6.1 first which will be supported by your 6.0 cluster and you need to use IPM-based communication
Then you can install 6.2 cluster and this support 6.1 CPS
Mike