I think that is a right quotation: you are asking not only to change IDE enviroment but also porting from F4 to L5 the whole library that involve USB stack.
The two MCU are very similar, but who knows...
You have to consider that someone need also to do test on a real Nucleo board the ported firmware.
If you are not in hurry, I can do it for you on my spare time, I sent a PM