I would scratch Das and Corsair off that list. Das quality is not quite up to scratch considering the price. Corsair boards have non-standard bottom rows, so they're impossible to find replacement keycap sets for. CM are great quality for the price, but there are no really premium boards in their range. If you have a lower budget, they're worth a look. Deck tend to have ugly fonts, but otherwise their boards are quite good. Which leaves Ducky and Filco. Both really great. I'd add KUL and Vortex to the list.
I would place the KUL ahead of the Ducky and about on par with Filco. Really good build quality. Personally I also like that they come with my favourite switch type (MX Clears), but that's just a preference.
Also, the Vortex Poker II (60% size board) is similar to Ducky in terms of quality, but perhaps not quite as good. They come in backlit and non-backlit versions. The non-backlit version comes with nice thick PBT caps.
The WASD Code does indeed have backlighting. It's white.
The WASD and Filco come with Costar style stabilisers, the Ducky, KUL and Poker II use Cherry style stabilisers.
Also, IMHO, you're going about the selection process a little incorrectly. The switch type and how it's mounted make more of a difference to the typing experience than the brand. So I'd put the order of importance something like this:
1. Switch type. Browns, Reds, Blacks, Blues, Greens, Clears, Whites, Greys?
2. Plate or PCB mounted? Technically both types are mounted to a PCB, but plate mounted means there is an extra metal support plate that the switches are physically mount on.
3. Of next importance is the layout. Full-size, TKL, 75%, 60%? Do you need a numpad (full size), do you need dedicated arrow keys (TKL and 75%), how important is the placement of the arrow and edit keys (normal placement = TKL, odd placement = 75%), do you need dedicated F-keys (60%)?
4. Then you look at what brands offer the switch type you want, mounted how you want in the size board you want.
