mode, thanks for measuring. I made a diagram to organize the discussion.
(a): YMDK case inside height I mesured.
(b): Thickness from top of plate to bottom of JST port.
(c): Thickness from top of PCB to bottom of JST port you mesured.
I think you mesured part (c). Can you measure part (b)?
I don't have LFK PCB and ALPS switches, so I cannot measure them. However, if the length of part (b) is less than 11.2mm, it should fit in the case.
In my stock Filco and Phantom with Cherry MX switches, part (b) is longer than part (a) as shown in the previous post.
part (b) of stock Filco: about 12.2mm
part (b) of Phantom style: about 12.6mm