I will just say, when it comes to working for free, it's best to not pester. Inform of bugs, inform of regressions, but if you don't get a response, don't press the issue. They're aware of it. Put yourself in their shoes; if you're enjoying your time off with friends/family/whathaveyou, do you want to be pestered by someone you don't know as if they're your boss? Writing an emulator is almost universally done for fun, not as a service. Some authors are genuinely concerned about preservation, but they still aren't treating this as a day job. It's an interest, a hobby. If anyone sucks the fun out, for any reason, it only hurts the community as a whole. Give authors slack, don't breathe down their neck, don't ask when an update is coming, and let forever be. Everyone will win in the end.
I've worked in development, I've headed projects both paid and unpaid, and I know how it goes. If you do nothing else, offer words of support and thanks. Don't beg, plead, or pester a free project. All you do is invite anxiety and frustration. </harsh>