So my big question is: what percent of all transactions go to 0/unconfirmed and never actually verify? Is there any way to find this number and compare it to the percent of all credit card transactions which are reversed, transaction fees and CC fraud?

Most merchants are pretty accustomed to a plethora of possible fees and reversal scenarios for CC payments and as such have typically rolled an amount of expected loss into their business plans. The point of bitcoin is to make reversals impossible and blockchain errors rare - no matter what we do there will still always be a margin of error and a small bit of fraud. What's important isn't creating a flawless system, what's important is creating a BETTER system. If we can (provably) show that the expected rate of loss for BTC is drastically lower than credit card transactions and make it easy to use, merchants will adopt it more readily.