If you have a platform (e.g. a Raspberry Pi 3B+ or newer) capable of running Home Assistant, it is pretty easy to get up and running these days if you use the Home Assistant OS version. Just write the image to a drive, and boot the system. I was able to use HA's "HomeKit Controller" integration to add the FP2, and then I used the Hubitat Home Assistant Device Bridge (HADB) to bring the various FP2 Zones into Hubitat. This keeps everything local on my LAN, and the performance is very quick.
No. Just the Aqara app on your phone. The Aqara hub is not required for setup and configuration of the FP2 sensor.
I just tried adding the Aqara Skill to Alexa, and it was able to discover the FP2 devices without needing an Aqara hub. This obviously requires the the FP2 to be allowed to communicate with the internet.