Yeah, PayPal don't have a great reputation for being all that helpful, but you get lucky sometimes lol
What will trigger the hold on your business account is the change in activity. If it's been unused for some time, then all of a sudden starts to see money flowing, that will trigger a red flag at PayPal for sure. I would at least inform them that I am about to start using the account, so when they notice a change in activity, that's what is happening.
What you can do to get past the hold is perhaps sell one or two small things that you can afford to pay for yourself. Then wait until the hold clears before listing anything further. Just remember, get proof of shipping on those first item that ship out to customers, that will help get the hold taken off your account as quickly as possible.