I think [name_m]Caleb[/name_m] and [name_m]Thomas[/name_m] match (as a pair), and [name_m]Malachi[/name_m] and [name_m]Jethro[/name_m] match (as a pair). Since there’s not just one name that sticks out, I think they all go together fine.
I agree that it works! I think [name_m]Thomas[/name_m] is a little more classic than the rest ([name_m]Caleb[/name_m] is popular, but still retains that Biblical quirk that [name_m]Malachi[/name_m] and [name_m]Jethro[/name_m] have, imo), but the Biblical nature of them all keeps them together cohesively, too! I would love to meet brothers named [name_m]Caleb[/name_m], [name_m]Malachi[/name_m], [name_m]Thomas[/name_m], and [name_m]Jethro[/name_m]!