I think you have the right attitude and expectations for this resto. Setbacks like cracked frame and engine cases were some of the "pulling your hair out" moments I was talking about in my previous post.
Again this goes back to your ultimate goal. If you want a "numbers matching" Elsie you will have to repair rather than replace those problems which can be a real PITB depending on the "fix" the PO did.
Conversely, If all you want is a real nice resto that you can be proud to own and ride on occasion, decent used replacement cases and even frames turn up on Craigs list and Ebay on a regular basis. If
you find replacements from the same year (73 vs 74), it won't even have much effect on the value to a collector if you ever decide to sell it, so keep that option in mind. Don't sweat the "silvery shine"
in the oil too much. These engine share the tranny oil with the clutch and Aluminum clutch plates shill Aluminum when used so it's normal to have that kind of contamination. I still recommend a total
engine tear down and rebuild replacing all the bearings, seals, springs, circlips and any parts that are out of spec.
Here's a picture of the correct ignition cover and kick starter for your bike:
By the way here's a picture of what I started with to show you it can always be worse:
Here's a more recent picture: