Hello Stebiz, welcome to Using English!
If you look at #7, you can see that two different statements are connected by an "and". Neither action is connected to the other; and each statement will stand alone:
7a. Joel fed his budgie.
7b. Josh fed the cat.
When you can do this, neither clause is subordinate.
With #4, however, you can't do this:
4. The squirrel leapt from the branch, as the cat chased it.
"It" refers back to the squirrel in the first part. "As" shows that the time of the chasing was the same as the time of the leaping. So there's a connection between the two parts: the second part is subordinate to the first part.
With this in mind, do you want to see if your daughter can try the other sentences? Then we'll check them for her.
All the best,