@Mayendra @simondedman @Anders_ASUS
Having spoken to João Dias (tasker developer), I'm glad to be able to share a very positive update.
The solution appears to be very simple thanks to something called the 'logcat' trigger which was introduced into tasker a number of months ago.
All I had to do was assign the three buttons to 'do nothing' in the Asus settings and then get tasker to react to 'single_click null', 'double_click null' and 'long_press null' logcat triggers in separate profiles.
I then associated whatever tasker task I wanted which each of the three triggers.
Joao also has a dedicated youtube video showing how to setup an example logcat profiles here. It really is very easy. Please google 'tasker logcat'
For those of us with a Zenfone 6, I'm sure we can all agree this is an enormously more helpful use case than simply reacting to a snooze button though! If I wasn't already a tasker user and bought the app for this purpose alone, it would be more than worth it.
Perhaps our Asus developer friends might still look to expand the options available within the Asus SmartKey settings anyway which is all well and good to allow more to be done even without tasker. That said, I personally think it would be a good thing for any user to go down the tasker route anyway as it's just an all round awesome app.
Just finally, if you find this work for you, please do consider supporting João as much as you can through his patron site (sorry not able to post links but please google it)
I think this use case is the perfect example of why we all benefit from really talented independent developers complementing the functionality that the big hardware and software manufactures come out with, and so they deserve our full support. João in no way asked me to say any of this, but I do feel indebted to him as this just wouldn't be possible otherwise.
All the best everyone!