Babies with different last names & Same Parents

My Husband & I are currently trying to convince our rainbow baby. We have picked out names, but  the last names are different. I mean that in a way that if God lets us have a boy that he will carry my maiden name due to my family name ending with me if I don't pass it own & in honor of my dad who passed away when I was young. He is 100% okay with it because his family is HUGE, so plenty of people to pass their name down. We want 4 kids total & to adopt 1. Yes, we want a big family if God allows us to before anyone judges on that! Even if  we don't have a boy then atleast one of the girls will carry my last name. We will keep it as even as possible as to how many kids have each last name.