vCenter 5.5 to 6.0 Upgrade doubts

Hello everyone i am planning to upgrade our vCenters Servers (3) from 5.5 to 6.0

My doubts are these ones:

1. We have separated SSO domains, after the upgrade we want to replicate the three PSC is there anyway to do that? I mean repointing PSC between them.

2. Between two of the vCenters we have installed Site Recovery Manager, what considerations we need to have if we can replicate the sites?

Thanks you very much.