Your assessments, as usual are right on. But just one question .......... you say on Stevens' catch (denied), "but Holmgren failed to challenge the ruling on the field". Is he permitted to challenge a whistled call like that?
You can get a call changed from incomplete to complete, but any further action wouldn't be allowed (if the receiver had subsequently gained yardage, for example, the spot would still be at the point of reception, assuming the whistle blew).