Middle names i don't mind - there is meaning behind why you wanted to use it, so if you want to use it, use it. don't NOT use it because your sister has

my bro used my grandfathers name (robert) as a middle name for his son. we would potentially use it too. not that it's a fantastic, unique name - but because it has emotional attachment for me.

James is a throwback to your grandfather - if you want to use it, use it

really, how often are the middles names going to be used? it's not like you're going to use them all them time!