I'm Your Eyes When You Must Steal: On the Ethics of the Young Metallica

Something has been bothering me for quite some time now, and no one has been able to offer me a straight answer on it.  

Note: this is by no means a new controversy.  I'm not even entirely sure it constitutes as a "controversy."

Nonetheless, I offer you the following in the hopes of gaining better clarity on the issue:

Early 1982: Dave Mustaine leaves Panic to join Metallica.

July 1982: Metallica releases the "No Life Til Leather" demo.  It includes a song called "The Mechanix," credited solely to Dave Mustaine.

   
April 1983: Dave Mustaine is fired from Metallica.  It is rumored that Mustaine asks the members of Metallica not to use his material.  Metallica disputes this claim.

May 1983: Metallica records "Kill 'Em All."

July 1983: "Kill 'Em All" is released in the U.S.  It contains a track entitled "The Four Horsemen."  Dave Mustaine is credited as a co-writer.

 

Also: "Flashdance....What A Feeling" by Irene Cara hits # 1 on the Billboard Hot 100.

Late 1983: Dave Mustaine forms Megadeth.

May 1985: Megadeth releases "Killing is My Business...And Business Is Good."  In addition to an absolutely terrible title, this album includes the track "Mechanix," credited solely to Dave Mustaine. 



Question # 1: 
Does anyone know what (if any) legal action took place surrounding these three songs recordings?

Question # 2:
Regardless as to how the track was credited, was it unethical for Metallica to release a song that seems to have been mostly crafted by an employee who had been terminated?   

Question # 3:
Assuming that Mustaine's writing credit has assured him of songwriting royalties for "The Four Hoursemen" was it unethical for him to double-dip and re-release the song?

Question # 3a: 
Was it petty?

Question # 4:
Why is this such an overlooked aspect of the Metallica/Megadeth rivalry? 

Question # 5:
Do you think that perhaps Metallica's lawyers prevented this topic from being addressed during Lars' and Dave's little pow-wow in "Some Kind of Monster"? 

Question # 6:
Lars totally couldn't play "The Mechanix" at the intended speed, could he? (Be honest).

Question # 7:
Should Kirk Hammet be ashamed of the fact that he took so little artistic license with another man's guitar solo? (Cue 6:23 mark on The Four Horsemen; approx 3:42 mark for the other two recordings)

Question # 8:
Does anyone know if Mustaine played "Mechanix" on any of the Big 4 dates?  Because that would have been awesome.