This is a great list
I bookmarked your post. One question remains. Why 0 confirmations? Wouldn't it be completely risky not waiting until it achieved at least one confirmation?
I think of it like this...
0 confirmations = fast food purchase
3 confirmations = expensive dinner
6 confirmations = cool dirt bike
10 confirmations = 40 acre farm
Nope. In fact, I feel that 0 confirmation is safe for less than $500 as long as it fits a few criteria.
1. Inputs must not be unconfirmed
2. Transaction has a reasonable fee/kb
3. There isn't any competing transactions
4. The mining pools and nodes at geographically distributed areas have seen it.
Most mining pools do not accept transactions with spent inputs and would include whichever transaction appeared first. Also, majority of network has Bitcoin Core as their client. They relay which ever transaction came first and would ignore any other transactions with spent input in their mempool. Of course, you can ask a miner to mine the double spend for you but it isn't worth it for less than $500.
