In your place, I’d suggest being transparent in your listings that X number of sitters had had no issues with your dog, but one had experienced lunging. And that you’d consulted your vet and have a muzzle on hand in case prospective sitters might be more comfortable using one with your dog, or in case they need it. That way, whoever applies would self-select for your dog, which is a benefit to a pet — you don’t want a sitter who turns out to be unprepared if you can help it.
Many people who’ve been around animals for a while know they can react differently in different situations and with different people. And cheers for you rescuing your dog from such conditions. BTW, your dog is adorable!
My dog is a rescue, is highly reactive and has many of the same triggers that yours does, plus others. My husband and I are used to walking him and otherwise helping him to avoid or deal with them.
If I saw a listing that was transparent as I described above, it wouldn’t put me off. I’d apply if the sit were otherwise appealing and — key thing — if I thought I could restrain that size or breed of a dog, if triggering happened.