Sounds like gobbledegook.<quoted text>
What is that we believe is LUCA/MRCA?
Kong gave as a reply apples and oranges.
How do you define your most recent common ancestor?(given the entire alien seeding running as a main theme trough your life.)
LUCA would be found in Carpentras-soil or those of similar constitution to form a fatty cell-wall.
When? Take a huge ballparknumber, but really huge since it involves all life.
So if your question is about time between those events...