I have the ZW-L but am only running Lionel engines at this time. I do have a Williams trolley running on the inside loop, it is conventional and operates fairly well.
The ZW-L is programmed for tracks 1-4 and controls my Legacy H10 steamer and other Lionel engines very well. Having read the manual there is no information on running MTH engines specifically, that I could find, only vague references to running other engines.
I also inquired if the built in Powermasters in the ZW-L were in fact Legacy Powermasters but I was not able to determine that. An e-mail to Lionel only resulted with a response to read the manual.
I did read the Legacy Powermaster manual and there are instructions on running MTH PS2/3 engines but I’m not sure they are the same as the instructions for the TPC 300/400’s