I like [name_m]William[/name_m] “Will” for you. A bit more energy and [name_m]Will[/name_m] is a good nicknames!
A few suggestion:
[name_m]Frederick[/name_m] (Freddie, [name_m]Rex[/name_m], [name_m]Riko[/name_m], [name_m]Fred[/name_m])
[name_m]Russell[/name_m] (Russ)
[name_m]Benjamin[/name_m] (Ben, [name_m]Benji[/name_m], [name_m]Benny[/name_m], [name_m]Jem[/name_m], [name_m]Jam[/name_m])
[name_m]Hugo[/name_m] (Huey, [name_m]Huw[/name_m])