As part of asking this question, I tried to prove the first of the two scenarios was possible by inventing a combination of cards that could turn a land into an Aura. To my surprise, I was unable to do so.
This convoluted scenario was the closest I could come:
- Mycosynth Lattice (everything is an artifact)
- Bludgeon Brawl (everything is an Equipment)
- March of the Machines (everything is a creature)
- Ashaya, Soul of the Wild (everything is a Forest land)
Then activate the ability Havengul Lich gained from Dominating Licid to turn it into an Aura and attach it to a creature. Per rule 702.151b:
Attaching an Equipment with reconfigure to another creature causes the Equipment to stop being a creature until it becomes unattached from that creature.
But this almost certainly doesn't work, because either the continuous effects still apply and turn Havengul Lich into a creature (which will cause it to be unattached and put into its owner's graveyard), or the reconfigure rule will overwrite Ashaya's effect so that it isn't a land.
Anyway, is there a different combination of cards that can create an Aura land?