Good question! I'm looking forward to hearing these suggestions.
Answering the eBooks portion of your question:
I'm certainly not an expert on this. I am just reporting what I found on church library online websites offering ebook circulation. The ones I checked were using OverDrive.
OverDrive has a list of formats at:
I looked at the online catalog of several churches offering ebooks using OverDrive and they are using that list.