I think Wilbur might be a marmite name and people either love it and think it’s endearing or hate it because of the swine association.
I love both Wilbur and Harvey, though I prefer Wilbur’s nickname options (Wilby 
, Will, ?) over Harv.
wilbur is so cute!
I like [name_m]Wilbur[/name_m] a lot but [name_m]Harvey[/name_m] feels more easy going like your sons’ names. You also wouldn’t repeat initials.
A few nickname ideas for [name_m]Harvey[/name_m]:
[name_m]Huck[/name_m]
[name_m]Hal[/name_m]
[name_m]Hutch[/name_m]
[name_m]Hart[/name_m]
I like [name_m]Wilbur[/name_m] it feels cuddly but solid too! Wilby is so cool!! I used to call my guinea pig [name_m]Wilbur[/name_m]: Wilby, [name_f]Bee[/name_f], Willobee
[name_m]Harvey[/name_m] is nice too - clunky grandpa vibes. I guess you could do the nickname Vee, H, [name_m]Ari[/name_m], [name_m]Hart[/name_m]?
Team [name_m]Harvey[/name_m]. I get the appeal of the nicknames but if just trying to get to [name_m]Will[/name_m]- lots of other less swine options!
I do like [name_m]Hart[/name_m] as a nickname! Wilby is just so endearing to me.