Not sure if this has been said yet but, with the cost of lumber right now (at least in my area) and other parts and products, for just five hens you could get a small manufactured coop/run.
Erm... sorry, this is not a good idea. Those little prefabs are just terrible. They don't meet minimum requirements and you have to ad hoc ventilation, plus the materials are sub-par.
Kind of like using Ikea stuff as patio furniture... I actually have something like that going right now as I needed something to put my potted plants on and I hated that old desk. You don't want to know what it looks like now, but hey, 1/3rd of it is still capable of holding pots so I'm going to use it until it dies.
That's the reason we pound this issue, not to be pitb, but I can't even imagine the number of people who get those coops and regret it. Do they give up on chickens? How much money do they lose? I don't know.
OP, to get back to the reason for your thread... I want to encourage you that it shouldn't be too hard to install the HW Cloth instead of those vents. @3KillerBs had previously posted some electric metal shears that cost about $45. If you cut your metal siding straight enough, you could probably use it for the overhang. I have no advice on how to cut straight, you don't want to see what we did to our shed, lol, so we just covered it with trim. Circular Saws are heavy to hold sideways while up on a ladder!
1/2 inch HW Cloth seems to be everyone's favorite so it doesn't get clogged with dust or let in small predators. You can sandwich the HW cloth under trim boards or secure it with washers and screws. I think your shed will make a great coop and you'll have so much space for storage!