They sometimes dig several test holes. . .maybe to fool a predator?. . .maybe just looking for the ideal spot, but quite often the 'real' nest is right around the mouth of the burrow. Since she came from a household with males and females chances are good the eggs are fertile.
My husband died in '83, and several years before he died he went on a motorcycle trip that had him coming home through the Mojave desert. He stopped at a roadside stand and bought me either a packet of saguaro seeds or a tiny 1" potted saguaro, I can't remember which. At any rate, for the past...
Yes, it's subtle - crowding at the food, sitting or peeing on the food, what is misconstrued as cuddling, sleeping in the same burrow, then blocking the door so one can't get out, following, etc. I'm a firm believer it's also mental, with no outward signs.
I use a 3/4 hp sump pump that carries the water to a Skippy filter and the discharge is about 2' over the pond, so it makes a pretty good splash. A good circulation current is noticeable.
Who knows what goes on in that little pea brain. I go around every evening and make sure everyone is away in their shelter and I block the opening to keep them safe.
Just a word of advice from a desert tortoise keeper of over 30 years: it would behoove you to separate that beautiful enclosure...