Twin boys - stuck on names?

My sister recently gave birth to twin boys, and they can’t seem to settle on a name.
They already have a son named [name_m]Olav[/name_m] [name_m]Daniel[/name_m]

She likes the names [name_m]Jonah[/name_m], [name_m]Abel[/name_m], and [name_m]Nicholas[/name_m], and would definitely not name them something that rhymes or sound identical.
Personally, I love the thought of [name_m]Jonah[/name_m] and [name_m]Abel[/name_m] - I think they sound good together.

So, can you come up with some suggestions that would work nicely together, and without being matchy-matchy?
And FIRST NAMES only please that’s what’s most important right now…

I agree either [name_m]Jonah[/name_m], [name_m]Able[/name_m] or [name_m]Jonah[/name_m], [name_m]Nicholas[/name_m] from that combo. So maybe for mn combos
[name_m]Jonah[/name_m] [name_m]Erik[/name_m]
[name_m]Jonah[/name_m] [name_m]Harris[/name_m]
[name_m]Jonah[/name_m] [name_m]Oliver[/name_m]

[name_m]Able[/name_m] [name_m]Conrad[/name_m]
[name_m]Able[/name_m] [name_m]Jacob[/name_m]
[name_m]Able[/name_m] [name_m]Roland[/name_m]

[name_m]Nicholas[/name_m] [name_m]Brant[/name_m]
[name_m]Nicholas[/name_m] Torbin
[name_m]Nicholas[/name_m] [name_m]Henry[/name_m]
[name_m]Nicholas[/name_m] [name_m]Walter[/name_m]

I tried to use a classic European ([name_u]North[/name_u]/[name_u]West[/name_u]) and biblical influence. [name_f]Do[/name_f] any of these strike their fancy? What types of names have they been gravitating toward?