@Sarah3478 I'm sure you'll be a great host, you sound very responsible and savvy. But one of the reasons that listings and reviews can't be transferred is that the listing is really all about the host, rather than the place itself. Even if the house remains the same, if someone took over who wasn't a good host, just in it for the money, guests might find that it was dirty, or that things weren't working properly, or the host wasn't responsive to messages, or rude, anything really that could turn a good listing into a bad one.
There are nice, large, even luxury places that have the potential to be 5* across the board, but in fact don't have good ratings because the host doesn't pay attention to the cleanliness or the upkeep and has poor communication style. And then there are very simple, small, basic places that get consistent 5* ratings because it's super clean, well-looked after and the host is personable and attentive.
The guests will probably be fine with there being a new owner/host, I just don't think it's something that should be sprung on them at the last minute. I know that house sales can sometimes drag on for awhile, so I can sort of understand the current owner's attitude, to not miss out on bookings, but it could backfire for him with upset guests if he waits too long to let them know.