Gabriel Adam Howe is perfect. For the girl, if you want to use a name similar to
Diana, I'd choose
Diane Abigail it flows better.
Personnaly, I'd use
Abigail Marie.
I picture a little
Gabriel as a blond haired, calm and kind little boy. To me, a little
Diana has dark hair and is full of energy.
An Abigail is more like a blonde haired little girl, deep blue eyes and pretty smart. But that's just because of my daughter.