1) Here they are
$ ./tezos-client rpc get /chains/main/blocks/1/context/contracts | grep KT1
"KT1WPEis2WhAc2FciM2tZVn8qe6pCBe9HkDp",
"KT1W148mcjmfvr9J2RvWcGHxsAFApq9mcfgT",
"KT1VvXEpeBpreAVpfp4V8ZujqWu2gVykwXBJ",
"KT1VsSxSXUkgw6zkBGgUuDXXuJs9ToPqkrCg",
"KT1Um7ieBEytZtumecLqGeL56iY6BuWoBgio",
"KT1TzamC1SCj68ia2E4q2GWZeT24yRHvUZay",
"KT1TcAHw5gpejyemwRtdNyFKGBLc4qwA5gtw",
"KT1THsDNgHtN56ew9VVCAUWnqPC81pqAxCEp",
"KT1SLWhfqPtQq7f4zLomh8BNgDeprF9B6d2M",
"KT1RUT25eGgo9KKWXfLhj1xYjghAY1iZ2don",
"KT1QuofAgnsWffHzLA7D78rxytJruGHDe7XG",
"KT1Q1kfbvzteafLvnGz92DGvkdypXfTGfEA3",
"KT1PDAELuX7CypUHinUgFgGFskKs7ytwh5Vw",
"KT1Msatnmdy24sQt6knzpALs4tvHfSPPduA2",
"KT1LZFMGrdnPjRLsCZ1aEDUAF5myA5Eo4rQe",
"KT1LQ99RfGcmFe98PiBcGXuyjBkWzAcoXXhW",
"KT1Kfbk3B6NYPCPohPBDU3Hxf5Xeyy9PdkNp",
"KT1KRyTaxCAM3YRquifEe29BDbUKNhJ6hdtx",
"KT1JW6PwhfaEJu6U3ENsxUeja48AdtqSoekd",
"KT1HvwFnXteMbphi7mfPDhCWkZSDvXEz8iyv",
"KT1Gow8VzXZx3Akn5kvjACqnjnyYBxQpzSKr",
"KT1FuFDZGdw86p6krdBUKoZfEMkcUmezqX5o",
"KT1FN5fcNNcgieGjzxbVEPWUpJGwZEpzNGA8",
"KT1FL3C6t9Lyfskyb6rQrCRQTnf7M9t587VM",
"KT1EWLAQGPMF2uhtVRPaCH2vtFVN36Njdr6z",
"KT1DnfT4hfikoMY3uiPE9mQV4y3Xweramb2k",
"KT1D5NmtDtgCwPxYNb2ZK2But6dhNLs1T1bV",
"KT1Cz7TyVFvHxXpxLS57RFePrhTGisUpPhvD",
"KT1CSKPf2jeLpMmrgKquN2bCjBTkAcAdRVDy",
"KT1CM1g1o9RKDdtDKgcBWE59X2KgTc2TcYtC",
"KT1A56dh8ivKNvLiLVkjYPyudmnY2Ti5Sba3",
"KT19xDbLsvQKnp9xqfDNPWJbKJJmV93dHDUa",
2) addresses need a minimum balance to exist, 1 mutez is the minimum possible balance
3) different allocation pools, early backers are explicitly encoded, contributors to the fundraiser represented as commitments
4) it's the other way around, when a blake2b hash of the tz1 address, keyed with an activation code, is taken, it should match the commitment address. Activation codes are included in blocks as an operation.