Looks like an old muso is caring about a poor muso.

Here're my answers.

Scenario 1
Maybe a poor muso should be more concerned about getting food than getting fame and money. If you can't sustain your life, what's the point of becoming famous?

I do this all the time. Going to TikTok Hong Kong, Taiwan, Japan, and listen to their popular songs, and if the melody is good, I'll just take it and use it in my own songs. Of course, I will change a few notes here and there, fill with new lyrics, make a new BiaB backing, then it becomes a brand new song.

Scenario 2
Rule Number One: Never try to sue anybody. The time and money spent on litigation are not worth it.

Rule Number Two: By the time when you get sued, you already have the resource to reach a settlement. Nobody wants to sue you unless they know you have fame and money.

As to posting to the User Showcase forum, a simple publishing service provided by a distributor would suffice.

For 99.9% of the people in the muso community, the most important thing would be: "How can I get famous, so other people will be interested in suing me?"

A Canadian music producer, singer songwriter, composer, and professional guitarist.