Ooh, since this is a safe space for dorks, I would like to be pedantic myself. Thank you for the opportunity. The oxygen catastrophe was caused by cyanobacteria-like organisms, which are photosynthetic, but are not plants. But it’s true, all bio-mass matters!
Cloning, once you have done it once, is a dead simple process, relatively. Figuring it out the first time was hard, but since Dolly (the first cloned sheep, born at University of Idaho) there have been high levels of publication on sheep cloning specifically.
Anymore, anyone who can parse reasonably complex instructions and has access to the kind of facilities any large animal vet might have could do this. It takes more money than I personally command but an even slightly well off person could afford it.