The newest version (Rev.2?) of Kato lighting kits uses a constant current diode (not a resistor) to control the brightness. The diode provides constant current (LED brightness) for a range of voltages. Yes, these are safe to use in DC and DCC.
Personally I think the brightness is acceptable. After all, it is only a single LED and a special light conduit which diffuses the light for the entire length of the car. Tp be honest, with the advent of tiny LEDs. I prefer ligthts which use multiple LEDs on the light s trip.
But if you want to decrease brightness you could install an extra series connected resistor. Since the resistor will limit the current to less than what the constant current diode regulates, it will pass all the resistor-limited current tot he LED.
The original FR11 decoders were made for Kato by Digitrax. I played with one few years back and it functioned as expected. I don't recall if it had solder pads for additional functions. I doubt it. Not sure if it even has a dimming feature for the lights, but my experience with Digitrax decoders in general talls me that they do nto handle LED dimming well.
Again going by experience, ZIMO version (if capable of dimming) would handle that function better.
While I like DCC, to me it is sort of waste of money to have DCC controlled lighting. But others might find it useful.
ESU sells multi-LED lightning strips which have a decoder built in. If I wanted to control lights in my coaches, I would likely go that route. Not as easy as plug-n-play like Kato, but I think the lighting would look better. Have not tried them yet.
Here is the decoderized one (for $24)
https://sbs4dcc.com/products/esu-50708-passenger-car-lighting-kit-warm-white-digital-set.htmlAnd no decoder (but has brightness adjustment) (for $20)
https://sbs4dcc.com/products/esu-50700-passenger-car-lighting-kit-warm-white.html