Completely different: Every thirty seconds, Elspeth looks around the room and says "There are N people in this room." Allirea is in the room, fading in and out. Can Magic tell when what Elspeth wants to say is false? Does it matter if Bella is in the room?

This one fails trivially. Elspeth has, in the past, without so much as a twinge from Magic, neglected Allirea's existence verbally and explicitly:

Siobhan pursed her lips and closed her eyes. "Elspeth, how many children does Joham have?" she asked, slowly and carefully.

"Three," I said.

"And their names are, from oldest to youngest...?"

"Noemi, Nahuel, and Iseul. Don't you already know -"