I like the whole idea of Han calling Luke kid forever and Luke being like I'm the same age as your wife Han.
Oh, most definitely. Han 100% calls Luke “kid” from the minute they meet in Mos Eisley till their deaths in extreme old age. (Like, old age such that Luke starts making Yoda jokes about “when 100 years you reach, look this good you will not.”) Han and Leia’s children and Luke’s students (many of which, let’s face it, are pretty much adopted children of his) all find it hilarious.
Han: Hey, kid. How’s it going?
Luke: Han. I’m the same age as your wife. We’re twins. In fact, I’m the older twin.