Sherri, I love your graphical designs and the themes so I truly do hope IBTheme makes a return. I would make the following recommendations for you to get this under control first.
First, drop all third party plugin support, if it works it works, but that is about it. Don't put them on this site directly as it makes more work for you to update and keep themes working.
Second, pick your favorite themes and focus on this, maybe up to 5 and push those for a bit and get yourself back into a system of keeping them up to date. Once you get them running fine with updates, add in number 6, then 7, etc.
Third, drop all the holiday themes for now, perhaps make holiday banners for the themes you choose to keep going with and such. These have been a burden on you since day one and they have too many time restrictions to keep customers happy.
If you have to, even go ahead and turn IBTheme into just a showcase and support platform and run all your sales off the official store. I understand that isn't great, but baby steps are needed at this time and most of us will be happy to see you back up and designing in some limited format instead of you trying to give us the world and being stuck in place.
None the less, that is just my two cents and you stay healthy and happy out there in this time of disaster.