Thank you so much for your kind and informative reply! We do have lots of predators in our area, including foxes and coyotes, so we are trying to make sure to build a very secure coop. I'm ordering a BIG role of hardware cloth! Also, there are several inches of snow on the ground here, so I'm sure you can understand why I can't/don't want to rush coop construction. Thinking outside of the box (coop!) for a temporary solution to buy us time.
One question I thought of: will the chickens need walls around their roosts to feel secure? So far, the pen plan is basically 2x4 framing covered in hardware cloth. Edited to clarify: the TEMP garage pen being the 2x4 framing. Also, to answer your 1st question... totally new to chickens!