Yes, the Ninja V supports 4K recording at up to 60 frames per second via its HDMI 2.0 connection.
It is powered by Sony NP-F (L-series) type batteries or via the included DC power adapter for continuous studio use.
No, the Ninja V is not waterproof or weather-sealed. It should be protected from rain and high-moisture environments.
Rental packages typically require you to provide your own AtomX SSDmini or compatible 2.5" SSD, though some kits may include them.