How do I remove keycaps on these switches?
Use a keypuller. I only have wire ones, and they do fine.
Focus Electronic used an absurd number of different switches in their keyboards, in a Chicony-esque way. The original FK-2001 (which itself changed design) used blue complicated Alps, Type IV clones, some sort of clone alleged to be Omron, and apparently (and I don't have a reference for this) white complicated Alps (listed here:
http://deskthority.net/wiki/Focus_FK-2001). I'm not 100% sure that "Type IV" is one switch — I've got an NTC keyboard that's got something
most the same, and that's what I posted to the Deskthority wiki, but it's not quite the same as what Alps.tw photographed as being in the FK-2001. Hard to differentiate manufacturing differences from clone jobs. I think I've nailed down what's an APC switch due to them having a reinforcement groove in the rear contact plate leg. APC is much easier though as their switches are still in production. So are XM switches, but no-one seems to have a photo of a confirmed XM switch disassembled (e.g. Filco Zero XM, Ducky 10**XM etc) and Xiang Min's spec doesn't go into enough detail.
I know the later version with Windows keys used Type III clones — I don't have a reference for those using anything else, but it would not surprise me.
(Focus's sales mailbox is
still full and still bouncing mail!!)