Perhaps it's a dead end, but I don't understand the reference to iTunes in this Console entry:
Mar 9 18:53:26 Richards-MacBook-Pro com.apple.xpc.launchd[1] (com.apple.xpc.launchd.domain.pid.Photos.7521): Path not allowed in target domain: type = pid, path = /Library/Frameworks/iTunesLibrary.framework/Versions/A/XPCServices/com.apple.iTunesLibraryService.xpc error = 147: The specified service did not ship in the requestor's bundle, origin = /Applications/Photos.app (Emphasis added)
I don't have any experience with that error, but it appears that it's some sort of security that blocks added or modified elements within a protected application from running. (so if some malware patches a legit app like iTunes by overwriting one of its components, it won't run)
"The specified service did not ship in the requestor's bundle" -> "this doesn't look like an original part of the application"
