It will be good to list which specific click variant (Tactile (MX6C-T3NB) or Click (MX6C-K3NB)) each one of the off-the-shelf keyboards and the Dell module have. Can be useful for someone that wants to buy some of these keyboards without testing it, or wants to know which specific switch he tested when trying some of these keyboards. Also list if there are variants of these keyboards/modules with different switch variants.
Add thiis handwired project to the README, is a great non-SMD-PCB alternative for mounting and soldering the ULP switches (see images in second comment link):
Maybe is possible to use the Dell module to get switches in addition to keycaps? Possible (or not) methods:
Desolder the switch
Use the soldering iron tip to heat the switch SMD pads from above, I don't know if you can have access to them from the top, maybe drill the switch a bit to access it?
Use a hot air desoldering station to heat the back of the PCB and the top of the switch (damages the switch?)
Drill the PCB from the back to access the SMD pads to desolder them using the soldering iron tip
Cut the PCB without desoldering the switch and reuse PCB fragment+switch.
Maybe you can use a hacksaw / Dremel mini-saw to cut the PCB in single switches squares or multiple switches rows/columns and then handwire them amoeba-style on your keyboard with the layout you want.