Why would it matter how much you checked into the person as far as the issue of getting to know them naturally? This is part of your OP.
People who are a reference will either have the time or not in order to answer questions and the person asking can get a feel whether it is inconvenient due to COVID or the person’s reluctance to answer questions about the single in question. COVID did not patur anybody from getting married and most people would be willing to help in that matter, so your latest point still is not relevant. Once the single finds out that those references are not valid, they should replace them with something appropriate. People who know how to ask questions will follow whatever trail is available for them to follow and many people do not even use the actual references very much, preferring instead to find out information from independent sources.