1. Given that not even Zooko understands zk-SNARKs, the ZCash name is trademarked, and they've shut down their Reddit and IRC channels, there is no chance of a community of competent developers that understand the technology springing up. Also I wouldn't be proud of forking Bitcoin, especially when the changes that have been made are so substantial that they can't keep in sync with upstream.

2. No, it's not in my hands to do so. The onus is on ZCash to demonstrate this the way any other cryptography is proven: peer review, and time. ZeroCash has little of either.

3. Anyone that sees it as an advantage has no clue about disincentives or game theoretic attacks.

4. The exact point of failure is that they all booted off the same ISO that was provided by one person. Additionally, when an observer at one of the stations had their phone compromised they didn't shut the ceremony down and restart, they just continued. Also, the participants are just Zooko's buddies - who's to say they aren't conspiring together, and merely compromising the procedure for anyone who isn't part of that (e.g. Peter Todd)?

5. If privacy is not the default, and is immensely hard to use (due to the system requirements), it will hardly be used. The entropy of the private system will be restricted to a relative handful of users.