So I have been using a number of nice looking Rf based light switches that don't require a neutral with a few broadlink rm pro and using tasker to carry out the automation part. I managed to use the broadlink app to enter into google home natively but it was all one way communication.
I now have 2 way communication and have managed to keep my switches as well as still not require neutral. Just thought I'd post here in case someone else has Rf based switches that wants to effectively make them two way communication (thanks to a few pointers here).
I'm using an esp8266 that gets power when the lights turn on. This is easily done with a usb wall adapter (I use a pass through usb adapter) if you already have downlights with plugs on them. When the light powers on it powers the esp8266 and the device sends a http get request to the maker api of hubitat.
So I know have updates when the switch is turned on at the wall. I also have google assistant commands working (previously if Google thought the switch was on because I manually turned it off last time I had to command on then off, now google gets uidates so no longer this problem).
The mods cost me less than $AU20 a circuit which is far cheaper than replacing the switches and I still retain no neutral requirement (only the zwave dimmer switches require no neutral which is common here in Australia and they would be far more expensive to replace the whole house 10+ switches which are already nice looking switches). Also with existing downlights with plugs I didn't even need any electrical work which you need a licence for here.
If anyone want more details I can post them but suspect I'm one of few to use Rf based lights switches with broadlink rm pro and hubitat.