Wow, I have never heard of that happening before. Obviously check your resistors to make sure they are correct. The only other thing I can think of is maybe if you mounted them flush against the PCB they overheated as they didn't have any air flow-seriously doubt that though.

I do both steps: remove the resistor AND cut and tape the ground. You can never be too safe.

Per replacements I LOVE Comet. Great prices and great quality. The reality is most of these bulbs come from the same factor and just have different names stamped on them.

If you want to LED the beacons as well, you will need to step down the voltages. Here is a little guide I put together of GRUMPY's method: https://pinside.com/pinball/forum/topic/f-14-tomcat-beacon-diy-step-down-voltage-regulator

I'm not sure what would have smoked a resistor like that. Was it just the one?