Yep, long chain of quests :)
You get your first shadowmourne quest from Darion Mograine standing West of where you enter. You need "Light's Vengeance", 25 Prim. Saronites, and the 2 abomination's blood to complete the 1st quest.
Yes it is obtainable in plant population
Unobtainable.
There is no word yet as to how Darkrai will be obtainable. Most likely it will be through some sort of real world event.
Ore-wise, it's Coal. But stone, is (obviously) the most obtainable material.
you can't because he is an un-obtainable boss character,and he is one of the kowloon co. the only digimon that are not obtainable.
maximum obtainable output
No it is not
It was obtainable on his birthday from what I heard.
It is possibly obtainable.
A zweibelane is a compound obtainable from the onion.
Lions are wild animals and are not "obtainable".