About your second question: what firmware are you on? The latest firmware 2.2.0 has a new feature which allows you to select whether you want to move the remaining zones in the same sequential group when you stop one zone. The user manual:
https://raysfiles.com/os_compiled_firmware/docs/2.2.0/OSUserManual220(1).pdf
page 10, section 4.3 shows it.