Personally, I think of Hewlett Packard, but I think once you get past that association, it could be fine. It does have nice enough sounds.
With Conrad, Nolan, and Juniper, I don't think it goes that well because I find the other names classic and cool while Hewitt seems very "right now" if you understand. But, I do suppose it's not much different from Beckett on your list.
I'm not much help! I think if you love it, then it'd be fine to use since there's no negatives really about it.
I like the feel of it, but I too think of Hewlett Packard. It also reads as an imperative sentence: "Hew it!" (as in, go hew some wood!). Finally, it doesn't quite fit with Conrad and Nolan, your other boys, as well as the more classic suggestions you were considering earlier.
Names with a similar feel (which again I like in the context of your family):
Thanks all, back to the drawing board!