Add a Node-RED controlled BLE LED as a full bulb

Hello everybody!

I need some help with my setup for a custom made LED solution controller via Node-RED with BLE. The goal is that this LED is seen as a light in HA. So that I see a light device in HA. I hope somebody can help me. I read some examples and was unable to find the solution for me.

Setup
Adafruit Feather with BLE and a neopixel LED. The neopixel beams the current colors to my LEGO Empire State Building. Just a small gadget I like. Every day around 17:00 Node-RED reads the current color scheme from esbnyc.com. This pattern is then send to the feather via BLE. When Node-RED sends the signal to go on, the LED will show each color for 10 seconds. Every 4 hours Node-RED will read out the battery level as well.
Send: on and off
Read: battery level

Current
I can in Node-RED easily make this LED a light bulb in Home Kit via the palette Home Kit. Homekit can turn the neopixel on and off, and it knows the battery level.

Wish
But I want that Home Kit gets their lights from HA. HA will be the core of automation and HK is just for the iPhone thingies. So, what is the best way to communicate to Node-RED and let HA know that it is a light bulb?

I read that it is not possible to add your own created not certified HK devices to HA. Please, correct me if I am wrong.

Thanks in advance!

If it shows up in the homekit integration in HA, you can use that entity in nodered. Do not use any specialty homekit nodes.