Sure, it's just not science, that type of question is philosophy.
It is absolutely not a coincidence. The sun puts out a lot of EM radiation and the highest intensity is around the 400 to 700 range so it makes perfect sense that evolution would favor eyes that detect light in that range.
I agree that animals see different things, not so much different beings though. Many insects and some lizards that I am aware of see in the ultraviolet light frequency. So they probably see some things differently than we do. Many mammals do not see colors, so you could put a dog and a person in a room lit by a red light and the person could easily see and the dog could not.
OK.
Yes, the sky would be blue, you just wouldn't have a word for it.
If I give my dog a treat, he likes the smell and the taste of the treat, even though he doesn't have a word for smell or taste.