I think Alexander Coleman is a regal name, I like it, especially with a monosyllabic last name. I don't like John so much probably because I don't like to shorten things, so I like Johnathan but, not really john, but Johnathan seems kinda fussy as a middle name. Just my opinion.
I also feel kinda strange about middle names being the same as possible first names (few people have Coleman as a first name, many have john) but it is kinda silly for me to even bring it up because I picked my middle name as Elizabeth which is totally a first name being use as a middle. Though my names were chosen with a few nods to where I came from, much like what you are doing so I didn't have many choices.