You could create a domain model like the one below:
Then create two json structures like this:
[{name:"test"}]
[{name:"test",
boolattr:true}]
From these json structures create two export mappings:
Then create the microflow for posting the data with these 2 mappings:
For the overview of the buttonArray page you can use the generalization to display common elements and add 2 buttons for creating the different button objects (or create an intermediary page allowing the user to select what knd of button he/she wants to create)
Now the post action will allow for posting the data with or without the boolean. You could even replace the button entity with the generalization like below:
Hope this helps you in creating the solution.