I will attempt to answer each of the questions in this single reply. Firstly, the common genes which can only be adopted through ancestry. Well do you have a good example? The gulo gene isn't one in my estimation, but I would be interested to see some other examples.
Receiving an organ off a person in the street as you put it, is totally different. I am not talking about tissue match to help with immune system issues (rejection). I am talking about arterial mapping, pressures, muscle thickness etc. Are you trying to say that a chimp heart would work properly in a human and anatomically be easy to install?
Am I saying that if Chimps and Humans came from a common ancestor, that I believe they would be identical in every way? Well of course not, but I would expect far more commonalities. Look at the ancestors of Wolves, Dogs. Now they have the same eyes, inner ears, skin, the fur is the same, the bone density is the same, their organs are the same. This is what I would expect and exactly what I observe. So, with Chimps and humans coming from a common ancestor AND being VERY closely genetically matched, I would expect to see at least ONE commonality. Don't include things like social behaviour, this is learned, not inherited.
Changed my mind and became a believer in the bible? Nope. I have believed in God all my life and will continue to do so. With the tiny amount of knowledge that man has, I ignore it when people say God is not required. My Universe and Earth will die, like an Atheists, but I will go on. There is no point whatsoever to life without God because there will be nothing left, not even a living thing to read our accomplishments.