They support phased restart, more in line with how puma does a full reload. This is more useful IMO, provided you have multi threading enabled. With pure process concurrency you have a higher memory overhead though, as the master doesn't preload the app before forking, preventing copy on write savings.
Yes, in the paid version, and it does so better than Unicorn (less memory usage, more efficient, more robust, better error reporting). See https://www.phusionpassenger.com for details.