[name_m]Hi[/name_m] there.
[name_f]Susannah[/name_f] & [name_m]Jonah[/name_m] are lovely.
Here are my thoughts on your list:
[name_m]Rocco[/name_m]-This is kind of different & unexpected, but I don’t know that I like it. It just sounds a little macho.
[name_m]Jacob[/name_m]-This is a nice solid classic. It’s obviously way over done though. But I love the nn [name_m]Jaco[/name_m], which sets it apart a little & would be adorable w/[name_f]Zuzu[/name_f] & [name_m]Jones[/name_m].
[name_m]Theodore[/name_m]-Ooh, very handsome & fits in perfectly. It’s getting a bit common if that bugs you, but no where near as much as [name_m]Jacob[/name_m]. Lots of great nns too! [name_u]Theo[/name_u], [name_u]Teddy[/name_u], [name_m]Thatch[/name_m], Thax.
[name_m]Anthony[/name_m]-I don’t personally love this one, but it’s not bad. [name_u]Tony[/name_u] is just kind of mob sounding to me, even though I know it’s a normal non-mob name.
[name_u]James[/name_u]-Very handsome. Sort of close to [name_m]Jones[/name_m]. The nn [name_u]Jem[/name_u] would be perfect though w/your crew.
[name_m]William[/name_m]-Another solid pick that is kind of too popular & not super interesting. I do think that [name_u]Billy[/name_u] is adorable though.
[name_m]Clarence[/name_m]-This is different, but I’m not sure we’re ready for a comeback yet.
[name_u]Jordan[/name_u]-Meh, this seems a little trendy & dated w/the charming classics [name_f]Susannah[/name_f] & [name_m]Jonah[/name_m].
[name_m]Jasper[/name_m]-This is not my personal favorite, but it works well for you. Jass & [name_m]Jones[/name_m] are sort of close for brothers.
[name_m]Julian[/name_m]-I love it! It’s one of my favorites. It goes nicely w/[name_f]Susannah[/name_f] & [name_m]Jonah[/name_m]. The nn [name_u]Jude[/name_u] especially.
[name_m]Gabriel[/name_m]-This is beautiful. Fits in great, and lots of great nns here too. [name_m]Gabe[/name_m], [name_u]Gaby[/name_u], [name_m]Gib[/name_m], [name_m]Gibby[/name_m].
[name_u]Grady[/name_u]-This is sort of a different style, but I think it’s kind of cute & sporty. [name_u]Grady[/name_u] [name_m]Graham[/name_m] isn’t the best, but it’s not a deal breaker.
Other suggestions-
[name_m]Arthur[/name_m]
[name_m]Aaron[/name_m]
[name_m]Benjamin[/name_m]
[name_m]Bennett[/name_m]
[name_u]Dexter[/name_u]
[name_u]Elliott[/name_u]
[name_m]Eli[/name_m]
[name_u]Elias[/name_u]
[name_u]Elisha[/name_u]
[name_m]Gordon[/name_m]
[name_u]Ira[/name_u]
[name_m]Louis[/name_m]
[name_m]Levi[/name_m]
[name_m]Milo[/name_m]
[name_m]Nathan[/name_m]
[name_m]Nathaniel[/name_m]
[name_m]Oliver[/name_m]
[name_m]Peter[/name_m]
[name_m]Samuel[/name_m]
[name_m]Simon[/name_m]
[name_m]Silas[/name_m]
[name_m]Wyatt[/name_m]
[name_m]Zachary[/name_m]
[name_f]Hope[/name_f] this helps. 
