As I said, turning blinking off works on LM Cinnamon, sounds like you need to raise an issue with LM and maybe upstream XFCE rather than making a way for Geany to force overriding it.
Scite is C++, Geany is C, Scite properties are handled very differently to how Geany settings are handled, so not much code is going to be directly reusable. Better to start from the Scintilla [API](https://www.scintilla.org/ScintillaDoc.html#SCI_SETCARETPERIOD).