I have a Google partition and want to know about Play store services and apps that require it. If I have Play store active in a separate partition with some apps that require it, when I'm not using the Google partition, is it still active communicating back and forth? Forth? And if I have a setup like this, what is the best way to minimize the impact of data being transferred back and forth? On my pixel? 5

When switching away from a session, you can press and hold the power button. One of the options should be "End session", which will stop all apps in that session from running and delete the profile's encryption keys from memory.