New Moto Guzzi Door Mats Available Now
When you pulled the starter was everything soaked with oil. I wouldn't touch it until the clutch starts slipping. Most Guzzis show that same outside oil; mist.
https://www.thisoldtractor.com/moto_guzzi_technical_training_videos_eng_v750.html
I suspect best practice is to just start removing parts from the rear wheel forward until I hit clutch lol.
Highly recommend using a heat gun to soften the 2-in-1 intake snorkel to pry off the throttle body or manifolds.
Your last picture of the trans and rear wheel together is IIRR how Guzzi installs the drive line at the factory. I think I have seen this in the manual??…
MG Cycle and Harpers come to mind for parts. Just make a decent order of any bits you may need since there is Int'l shipping.Tom