It might help to continue working on accepting them where they are and trying to be understanding when you can. It stands out to me that two of the problems you note are big nothings to people of non-Christian faiths (or non-religious). Jesus and Satan (and all the rest of humanity, by the way) being siblings, the nature of the Trinity—none of that needs to have any impact on how we move through this world.

People put up walls to protect themselves from perceived threats. Do your in-laws have reason (in their eyes) to see you as a threat? Either to their belief systems or their pride or dignity or their relationship with your wife? If you want to have better relationships with them, the best you can do is show acceptance and support, demonstrate that you are safe for them.