Hey guys! I created a little template that circumvents the issue of Functions behaving fundamentally different in Construct 3 vs Construct 2. I really liked Construct 2's Functions, as they behaved more like Events in a typical programming language. It is now my opinion, get ready to raise your pitchforks, that because Custom Actions for Objects now exist, Functions as they are now are basically useless.
That all said, it randomly hit me that with some AJAX/Dictionary trickery, I could just mimic the behaviour of Construct 2 functions. At this link you will find a breakdown of what I've done and a download for the Template .C3P. Enjoy!
https://www.construct.net/en/tutorials/using-ajax-event-signals-3128