We have a [name_m]Watson[/name_m]! We call him [name_m]Sonny[/name_m]. 
We have a [name_m]Sullivan[/name_m] (Sully) and a [name_f]Beverly[/name_f]. A little biased, but I think they are great sibling names for [name_m]Watson[/name_m]! 
Out of your options I love: [name_m]Griffin[/name_m], [name_m]Clark[/name_m], [name_f]Hazel[/name_f], [name_f]Elle[/name_f] and [name_f]Winnie[/name_f].
[name_m]Other[/name_m] options: [name_m]Conrad[/name_m], [name_m]August[/name_m], [name_m]Shepherd[/name_m], [name_f]Quinn[/name_f], [name_f]Zara[/name_f], [name_f]Joelle[/name_f] and [name_f]Elisabeth[/name_f].