So consider a powerline network adapter, or move the PC to a place you can run a cable.

Just use gigabit networking. You are looking ~4h/TB give or take depending on a few factors.

Store them on punch cards. They are cheap.

Most external 2.5" drives do not have sata connections. Only the 3.5" drives are a reasonable safe bet, and it’s still not a sure thing. Best to look up the drive before purchasing.

Yes. Be sure to mark the drive as bad so it does not get reused.

Just print them out frame by frame, make flip books, and she can carry them into any room in the house she likes.

Stop being lazy and just use punch cards like a real horder.

Backup data. Replaced failed drives. Eat cheese.