PoE Texas Raspberry Pi PoE Hat

Q: This listing shows 3 enclosures - what are the amazon listing codes ( asin ) for each of them? anyone know?

The clear case is used for visual display only, showing that the GAF-PiHAT fits perfectly over the Raspberry Pi 3 B+ board and does not interfere in any enclosure fitting. It is recommended to use an official Raspberry Pi enclosure to ensure proper fit.

Q: Im looking to use your hat to power some pi3s with the official 7 inch screen. i can pull power from other pins, but are you using the i2c pins?

This only connects to the first 3 pins in each row and the POE header. All the rest of the pins are accessible. You can also solder leads to a 5v 2a connection on the HAT for extra power.

Q: how to install fan when poe hat takes one of the pins to do so?

Assuming your fan uses 5VDC, there are a couple of pads labeled "5V 2.2A Out" on the POE board where it connects to the Raspberry Pi 40 pin header. You could solder a pig tail connector on those pads to support a fan.