Reusing PGC & PGD pins

[Demon]

are those switches meant to be active high ?...

They can be whatever they have to be so that it works perfectly. It's my circuit, and I answer to nobody (except those here that know more than me ).

...applying somewhat less than vcc to the pic input pins and all those extra components seems a recipe for non success....

Oddly, it's working as-is.

...i would use the weak pu and have switches active low....

I just checked, 16F18877 has WPUx register for all ports except pins E0, E1 and E2, so that's a plus.

I'm still doing research on all the processes I need, so the switches can easily become active low.

...don't press buttons when programming is not to much of a constraint...

Definitely agree, I never touch the circuit while it's being programmed.

That being said, is 10K a reasonable isolation resistor in this case?