Ura as a backup variation is one I haven't heard before but also makes sense.
Yeah, there's a big gap between photo 1 and 2 of the last example you give. It's also obviously a reversal with the original uke becoming nage, but very much start and end with no depiction of the middle bits.
The problem with these terms is the various historical and cultural understandings that mean different people use them in different ways, even in the same art.
Can't remember which one, but I recall going through the various old books posted on the Aikido Sangenkai blog and suddenly realised that one book showed 左半身 left hanmi with a picture of standing left foot forward and in another a picture of right foot forward (front of the body to the left side). If old documents don't even consistently describe left and right, what hope have we got for omote, ura, kokyu, aiki, etc.
Doesn't mean we shouldn't try to understand the common versions and where they can be based on a different point of view, so I like your original question.
The common blurring of irimi/tenkan with omote/ura also makes this unclear.