How do FLIR cameras work with multiple spectral image acquisition?
I have an FLIR E series camera, they work with two cameras (infrared and visible) and overlay the images on one another. Sometimes not very well.
The L[epton only works with infrared (not visible) and has two outputs][1]

Spectral range - Longwave infrared, 8 μm to 14 μm

The spectral range is the wavelength which is 8 to 14um

Output format - User-selectable 14-bit, 8-bit (AGC applied), or 24-bit
RGB (AGC and colorization applied)

The output format can be different bit formats meaning you can get a grayscale, or you can get an output that is mapped to RGB, but the datasource is the same infrared sensor.
If you want to use the Lepton, then you could use an arudino or other microprocessor to read the SPI output of the sensor
[1]: https://groupgets.com/manufacturers/flir/products/lepton-3-0