Read mine more carefully
Spamlines and LCC have nothing in common at all other then kinda the IFS cheat, but nothing to the extreme.
The overwhelming majority of LCC's have 1 or 2 families of aircraft, nearly none run anything other then economy some maybe have increased leg room company or PE neither of which the game simulates. Most Spamlines run everything they can get with 3 classes on all.
You will generally see only 1 seat arrangement per aircraft type for an LCC. Spamlines run whatever they had on the plane when it was bought used
The largest LCC has 707 aircraft all of the same family, with vast majority of them being less then 200 and many being less then 100. Spamlines run thousands of planes.