Hello and welcome to FT!
Correct. Always the actual airline that you fly with. Codeshare is irrelvant.
No, it is not 40,000 flown miles. It is 40,000 status miles. Status miles depends on the booking class. Some booking classes do not any status miles. Some earn as much as 150%.
"When you are progressing up through the tiers then your status boasts your Status miles. Correct?" Sorry not understood. Status miles will boost your status.