Is GSX level 2 included in the upcoming fs2020 version?
It's more or less included.
Animated Passengers and Fuel Hydrants, which were previously exclusives of GSX L2, will be included.
Jetways replacement will be included as well, but jetways will use the default system, since there's no SODE for MSFS yet, so you'll have more model variety, hundreds of different airport/operators logos around the world, but no support for the advanced features possible with SODE like parking spots with multiple jetways or the ease of user customization we had in GSX L2. On the other hand, all GSX vehicles will serve AI planes as well, behaving like default ground vehicles, but with GSX graphic and ample choice of operators.
So, what you'll get in GSX for MSFS it's more or less like a GSX + GSX L1.5, but with a single purchase.