Question - Are PL-Pro and Encore main stations (MS-232 and MS-702), (MS-440 and MS-704) and or power supplies (PS-232 and PS-702) compatible with each other?

Answer - Yes they are compatible, PL-Pro and Encore can be used together to build larger PL systems.  Intelligent power sensing allows the power supplies to work together to meet the power requirements of the PL products connected.

The main stations mentioned above have different power supply specifications, see below:
MS-232 - supports up to 60 single channel beltpacks or 20 speaker stations
MS-702 - supports up to 40 single channel beltpacks or 10 speaker stations

MS-440 - supports up to 60 single channel beltpacks or 20 speaker stations
MS-704 - supports up to 40 single channel beltpacks or 10 speaker stations

PS-232 - supports up to 40 single channel beltpacks or 15 speaker stations
PS-702 - supports up to 40 single channel beltpacks or 10 speaker stations

When connecting multiple Mains Stations together make sure that you only have one termination turned “ON” per partyline channel. The termination should be turned “off” on the other main stations

You also may come up against ground potential issues. This is not uncommon in these situations, as you are probably not going to have both systems on the same circuit. It doesn’t always cause issues, but just in case, have an MT-701 interface card standing by.

https://www.clearcom.com/product/mt-701/
This will dry out the 30 volts between the two systems, while allowing the intercom audio and call signals to “pass” through and be reconstituted at the other end, without actually passing that voltage used in call, through to the other system.