Out of curiosity, what are all the kid's middles?
I think it's okay...not ideal and maybe the kids will feel a bit possessive of the name. But my middle name is Michelle and one of my brothers has Michael as a middle, and neither of us mind. Of course, that's both middles, not one first and one middle.
Is Theodore a family name that you'd like to honor? If there's a certain reason you really want to use Theodore, go for it. If you're honoring a family member, maybe both the kids will just feel that special connection to that relative. If it's simply that you just like the name a lot, I would think about it a little more and make sure there's not another, more distinct name that you like just as well.
One other thing...is Easton a boy? That feels like a rather different style from Theodore. Not hugely different, but maybe a slightly more modern/surnamey boy's name fits better.
All that aside: if you just love Theodore Marshall, or if it's an important family name, I think you can totally get away with it. The combo is nice, too.
Personally, I would pick something else. Not only is it essentially the same name as your daughter's middle name, but PP is right - it doesn't have the same flavor as your other son's name. Maybe consider Marshall as a first name and choose a different middle name?
Thanks for the responses!
@tintri I agree it is such a great name.
@loisvs They are Nathaniel, Miles, Theodora, Finley and Mae.
We just really like Theodore because it crosses off things in a name we both like. It isn't a family name but I am starting to have doubts about it because of the similarities.
Easton is a boy, I agree about the difference in styles but between me and my husbands tastes we just want to find a name we both like.
@isabellemarie Thanks I agree too.
@thatkathryngirl I think we might be leaning towards a different name just because of how similar it is.