Huh, I have the same problem with a P2-S. The Mach3 plugin worked great and had lots of settings. The Mach4 plugin is just supposed to work, nothing in settings to change/configure. I don't think the Mach4 plugins are "finished."
I've not tried the F1/F2/F3 functions so can't answer to that.
The pendant doesn't follow your Mach4 jogging increments, it follows it's own!!! You can change increment by holding the side button and rotating the hand wheel while in incremental jog, but it follows IT"S increments, not Mach4's. I'm in INCH and I don't need it to go inadvertently to 1" increment!!! In Mach4 increment I just have .0001, .001, and .01, no 1.0!!! But the pendant doesn't follow Mach4's increments!!!
And I just learned last night, I'm fairly new to Mach4 after years with Mach3, that while running gcode the pendant drops back to the screen reading VistaCNC iMach4 and is dead until a Mach4 restart. I guess this is what you meant by "brick!" THAT one is NOT COOL!
Lee Neuman is the guy at VistaCNC, but he's spread pretty thin, it seems to me. Email him, support@vistacnc.com, and point him here, maybe he'll respond. I'll do the same because Lee and I had a dialog going because of another issue with his EE box and a P2-SE pendant not working, too. Hitting the eStop would "brick" the pendant until a Mach4 restart. Haven't resolved THAT one either.
Also, there is a forum here for VistaCNC, but no traffic down there!
These pendants are very nice, and in Mach3, no problem, but Mach4 not so good so far.