Max Graf - I have some ideas percolating which might be related to your ideas, so I am curious if you've considered making anything like a dachsie-catio. There doesn't appear to be an equivalent term like a "dogio", unfortunately.

It's wildly area-dependent, but the smallest breeds and puppies (rabbit-sized) can actually be endangered by raptors snatching them up. I had a mental image of a yard-tunnel - a wire passageway above-ground inside the perimeter or around a large area so they can "inspect" the grounds without a guard-human's attention.

I saw this cat-structure that seemed a bit inspirational, for an example:

Outdoor cat tunnel to sanctuary

I think something attached to the house, like a patio/deck/porch is the easiest for something like that. We are putting in railings for our front porch and a gate for pups to stay on the porch.

How complicated is a grass-touching sort of screened lean-to?

crumples up her ideas and pitches them over her shoulder as events refuse to cooperate I guess I'll get back to you.