Transforming After a double-faced card transforms, it's still the same card, so any Auras, counters, or other effects stay right where they are (unless the double-faced card's characteristics have changed such that an Aura can no longer legally enchant it)
The Order of the White Lotus + Here are more cards with lotus in their name that definitely behave differently than what you expect from a lotus, but the flavor is something to savor on Gather the White Lotus, Iroh, Grand Lotus, Lotuslight Dancers, White Lotus Hideout, and White Lotus Reinforcements
This was the first Dredge deck, the first to truly break the mechanic
MDFCs are all about making a choice between what you need now and what you might need later
In any deck that goes bigger, you just wont have many turns where you can spare five or six mana to use it