The easiest way I can think to do LEDs without a PCB (I assume that's what you mean by "free soldering" the switches?) would be to glue each LED to a switch, then the leads would be there to solder to. The leads are the other side to the pins so shouldn't be too hard to avoid shorts, but you will have a lot of wires to fit in the case.
Also if you glue them you won't be able to swap the switch springs/stems and may need to replace the switch if the LED fails if you can't get them unglued.