Hi!!!
Yes, pushbullet would be quite interesting to provide notifications or even to activate trigers, but please take your time, I'm in no rush!
As for esp8266 it is a programmable micro controller based on arduino. You have to program them to do something with their IO pins. You can have a button on two pins and program it so anytime someone pushes the button it triggers a sequematic action - that's the easy part.
The hard part would be the other way around since the esp8266 would have to be programmed with some framework for example, although it would be useful as you could create a sequematic that could send a command to them, just like any other smartplug.
There are some tiny webservers that esp8266 can run, perhaps that would be feasible with some kind of webhook
But hey, these are just some ideas, nothing you are obligated to! O do understand it is hard and that I am being very generic but perhaps that's the beginning of something useful, with an idea!
Thank you!