Any thoughts you have would be appreciated. 
Thanks!
I don’t think it’s too close. Your [name]MIL[/name] should follow your lead and just go with [name]Kellen[/name] too. If you like other names it might be worth considering them just to avoid the occasional confusion / misunderstanding that you named him after her, but if you love this name more than any other I don’t think this is worth missing out on it.