First, as far as the dog, it’s going to depend on the size of the dog. There are motion sensors which are “pet immune” which is just a fancy way of saying the sensitivity can be set so that only bigger creatures, typically over 40 or 50 pounds, will result in an alert. Then you can run into the opposite problem that those sensors won’t necessarily trigger for small child, would you might want if you’re also using them to operate lighting.
https://www.amazon.com/Ecolink-Z-Wave-Motion-Detector-PIRZWAVE2-ECO/dp/B00FB1TBKS
A lot of people will adjust the detection field so that it only starts detecting at about 5 feet off the ground, which might also make it work for a dog. So there are just various things you can look at for that particular issue.
As far as the doors and contact sensors, the new sensative strips, which are available on both the US and EU frequency, are just under 3 mm thick and are designed to fit in the door frame. They can also be painted which makes them almost invisible. They are expensive, but there are some deals available on them. A number of community members have them and like them a lot. So that would be something to look into for the French doors.
The steel doors are a whole different problem. Any magnetic reed sensor, which includes the sensative strips, is not going to work well on the steel doors. What happens is that overtime the steel itself becomes magnetized and then it confuses the sensor so that it will always read as closed even when the doors open. Not what you want, obviously.
You can get around that, but it usually requires lifting the sensor up off the door several inches and putting it on a non-conducting block, typically wood or maybe some plastics. Again, sometimes you just have to try it and see.