Given the massive price differences in Alpha and Beta on the secondary market (with Alpha once again nearing $1000 per box on TCGPlayer and eBay at the time of writing), these questions are to be expected
Oath of Liliana is legendary, just like the previous Oaths from Oath of the Gatewatch
In the main deck, we're hoping to stick surveil payoffs like Thoughtbound Phantasm and Dimir Spybug and grow them into real threats as we cast surveil cards
Green is good when you need to put lands into the graveyard, my simple solution is a budget land that fetches in Terramorphic Expanse, and the expensive solution is a fetch land like Misty Rainforest
This one costs five mana, and reads, Whenever enchanted player casts an instant or sorcery spell, each other player may copy that spell and may choose new targets for the copy they control. Its great for playing against control players, because then everyone can choose to counter their nonsense