That's the thing about Fungus. I had a horrible time trying to integrate Fungus with my scripting. You'd think it would be pretty intuitive to modify stuff like boolean values through scripting, but it took me way longer than it should've to access the Fungus variables.
My advice: put serious effort into learning C#. (Sololearn is a good tool for this, it's how I learned a lot. I'm not affiliated with them in any way.) Another thing to put some time in would be XML. It's very helpful when trying to define preset data values, like skills in an RPG. Once you get a good grasp on C#, see what you can do about making your own dialogue system. I've never personally gotten to making a dialogue system, but people have had to develop their own systems for years, so there's bound to be lots of documentation, if you take the time to look. This way, you can have a system that does exactly what you want and nothing more, nothing less.