We have bought the one in your first link and tomorrow morning we will start putting it up. Actually we will start the foundation and floor tomorrow. And we are using it for a duck house not a chicken coop. We were warned and are aware of the fact that it will heat up. Hubby will have a friend helping him and they will be doing a lot of framing with 2x4's on the inside in order to put windows all around it. Hubby's carpentry skills will allow for some massive adaptations but I remember a dog house he built one time and so yeah.....starting from the ground up was not in the cards.
We intend to also put insulation and a roof vent. I also intend to paint the roof with reflective paint. It will be in the shady part(mornings till lunch) of the yard. Afternoons when the sun hits it, we are hoping the covered run I intend to put on the front of it will help. But yeah, I think we can make it work for ducks. They will have plenty of water sources to get wet. There are threads on here where people have made it work for chickens...in the shade, under trees with PLENTY of ventilation.
We bought our coop used from a farmer who actually loaded it up and brought it to us on a trailer. It is 6'x12. Nothing but nothing is going to be able to tear into that old wood, it is sturdy. We paid $200 for it and made repairs and some changes. You might look around and find something like that. A child's playhouse, big doghouse, shed....anything close to the size you want that might be adapted. I have to be honest and say that when we started searching for something for the ducks, nothing was available, therefore the metal shed.
Eta: we will probably end up spending close to the cost of the shed to make the adaptations, mainly for plywood and 2x4's.
Someone has a thread where they turned the plastic shed in your last link into a chicken house and it was actually pretty cute. Good luck....have fun planning! Edited by Birdydeb - 6/7/16 at 11:32am