Some more documentation?

[ngppgn]

Hello,

I was just looking for ways to export parts of my app functionalitiws to allow for user customisation, so this repo has been a godsend to me. However, I have a fiew questions, if you don't mind, and maybe the anwer could provide potentially useful info for other users:
-you mention potential pwrformance issues, could you elaborate a little more on that?
-is is possible to 'grsb' something more than a single class instance from a script? Specifically:
-Can I instantiate several object in the script and get a hold of them in code?
+Can I define top-level functions in one script and use them in a later script?
-Can I define extension methods or properties for classes defined in the hard code?

Sorry in advance if my questions seem too noobish