Nope. Rhymes with F***. Puts a name automatically out for me. Huckleberry makes me think of dingleberry. Not a great image. Huckle is a little better, but it just makes me think of chuckle and I can't get that out of my head.
I think Huck as a nickname is the best option if you feel you must use it, for what, I am not sure. Huxley sounds like the best option but doesn't go well with your other kids and appears trendy.