You need to log in from time to time (not sure of how often) to avoid being restricted in height and distance. This happened to me once in a remote part of Idaho.
Honestly.. who would know really...But if your a part 107 pilot, they won't mind collecting your money any more than the fool at the football game.
But as you say, the FAA has no say indoors. So you would be fine anyway.
Yes. That's why I wrote that it may be a grey zone. However, it would be really a reach for the FAA to justify slapping a fine for a 135g drone intending to scan indoors for safety reasons.