What's up with people insisting that you need a lawyer to respond to a DMCA notice? That's some hilariously poor advice, like holy shit. I wonder if these same (presumably) rich idiots also hire a lawyer to read the terms of service when signing up for a service?

You absolutely do not need and should not spend money on a lawyer for this. The only way you're possibly going to get in trouble is if you're acting in bad faith, you don't need a lawyer to tell you if you are.