I really like
Bartholomew, I think it's very handsome. I really dislike
Bart, Simpson's association aside even. I don't like Barth, either.
Tolly would be my nickname of choice, but I'm not sure I totally love it. Too bad it's such a long name! It really does need a nickname.
I'd name a brother or sister anything else classic, but probably not both Biblical unless they're so mainstream they don't have that Biblical vibe (like
James or
Elizabeth). Or more fun, I'd go for the adventurey, outdoorsy vibe of
Bartholomew and pick more offbeat things like Wilder or
Merritt and
Mira or
Rowan.