Well it sounds like the bug mentioned by Gopher may be your issue. But I was checking to make sure you had a hub as I have ran into people with no hub complaining about lag or unresponsive actions because HomeKit running on a wifi device like a MAC never works well.
The button actions you are trying to do I successfully completed a few times. I’m using the top button of my Zooz scene controller as my overhead fan and as a switch, so I had to create a virtual switch with a two way mirror to get the to work right. If you run into doing that, feel free to ping me.
Soooo the zooz now shows up as a switch for the main load but nothing now appears for the other 4 buttons on the switch. How do I edit those now in HomeKit?
Enable Show accessories classes and characteristics at the bottom. That will allow a choice between exporting it as a switch or as a button. You can't do both at the same time. A workaround is to create a virtual switch and hook it up with some basic rules to the real one.
2.3.4.127 changed the button export behavior. If something is a button and a switch, it's exported as a switch by default. It's overridable, just like it was in prior versions, but default selection is different now.