I tried to run TYPO3 Neos 2.1 under MAMP Pro 3.5 (PHP 5.6.10 cgi). It doesn't work. I get a Doctrine DBAL Exception (Connection Refused). If i run php as a module rather than cgi, it works. But i want different php versions per host, so cgi is preferable by me. Phpinfo says pdo_mysql is active. Any ideas what is wrong with the cgi?
I had the same problem with MAMP. Sometimes the DB connection worked and abruptly the connection was lost and the db destroyed. I would try to use vagrant or even better docker. Just search for docker and neos on github: https://github.com/search?utf8=%E2%9C%93&q=docker+neos.
But if you really want to use MAMP, use PHP 7. For me it solved the problem. Hope this helps...
EDIT:
My Workbuddy wrote a nice shell command tool for Neos: http://sbruggmann.github.io/dino.sh/