Yes - there are a number of users using the MP 5,1 (it is one of our test systems here). There are a number of people on the beta team that are on that machine as well, so it gets plenty of testing. It works well.
The software works well on Mojave and Catalina (basically everything from 10.8.5 onward).
Cat5e or better is recommended. You need to ensure that they are at least Cat 5 (all 8 conductors, as MHLink requires a Gigabit connection).