All your sybil attacks are abstract and don't take into account factors of the real world. The attacks may succeed in a spherical vacuum, but what about attacking eMunie if it's used by, say, Starbucks? You walk into a cafe and scan a special QR-code (displayed on an interactive screen) with your smartphone. This code is the root of Merkle tree of the ledger essential part. If your version of eMunie ledger is "hacked" then you will see the difference right away. Whom will you trust, the Starbucks system or unknown random guy with 2 million fake nodes?