Brother or sister for Job and Len

For a boy: Job, Len & ...
Bas
Vic
Xim
Sem
Mil
Gio
Sig
Wes
Pim
Dex
Sep
Eli

For a girl: Job, Len & ...
Fia
Ans
Flo
Isa
Joy
Ona
Ita
Zoe
Fay

I don’t find Rox nice, but I do like Len and Job. Here are some other options for you:
(C, N, L, J not included)
Ief Pim Abe Ebe Rik Kay Kas Mas Tor Bor Ted Sam Sep Zev Tim Tom Wes Ivo Ipo Sol Raf Ole Dex Gus Fos Eef Don Bob Age Bas

Favorite combinations are:
Len, Job and Sep (the most beautiful, because of the sound of len and the p sound of job)
Len, Job and Pim
Len, Job and Gus
Len, Job and Bas

Job, Len and ...
Sep (Eden/Elijah/Elliot/Emiel/Emanuel/Ewout - Pepijn/Pelle/Philip/Phyllon)
Pim or Dim (Isaiah/Idze/Isaac/Imanuel/Ivo - Mads/Manuel/Merijn/Mason/Mathis/Maxim/Micha)
Riv (Isaiah/Idze/Isaac/Imanuel/Ivo - Valentijn/Valentin/Vigo/Vince)
Raf (Aiden/Alec/Alain/Arwin/Adam/Aaron - Fender/Fabian/Finn/Fedde/Ferron/Floris/Florian)
Sam (Aiden/Alec/Alain/Arwin - Mads/Micha/Maxim/Merijn/Manuel/Mathis/Mason).

Ela (Lana/Lauren/Leentje/Lena/Leone/Lise/Lieve/Lotte/Loïs/Lizzie - Amélie/Aike/Airen/Aileen/Amarins/Anouk/Aukje/Ayla)
Iva (Valerie/Viènn/Vajèn/Veerle/Veda/Vesper/Viviënne - Amélie/Aike/Airen/Aileen/Amarins/Anouk/Aukje/Ayla)
Sam (Amélie/Aike/Aileen/Airen/Amarins/Anouk/Aukje/Ayla - Mette/Milou/Madee/Magali/Maia/Malou/Melina/Merel/Marèl)
Fem (Eefke/Eleanor/Eline/Elin/Ellis/Elle/Emmie/Emily/Esmée/Evelinn - Mette/Madee/Milou/Magali/Maia/Malou/Melina/Marèl/Merel)
Ise (Sophie/Sammie/Seija/Sarah/Salomé/Selah/Sofie/Solane/Stella/Suze - Eefke/Eleanor/Eline/Elin/Ellis/Elle/Emmie/Emily/Esmée/Evelinn)
Evi (Valerie/Viènn/Vajèn/Veerle/Veda/Vesper/Viviënne - Ieke/Iloni/Imane/Imme/Indie/Isabel)

I'm not really a fan of Rox myself, but tastes differ. Job and Len are really nice! For Rox as the second and third name:
Olivia/Oona/Odilia/Ophelia/Olenna/Olcay/Oliva.
Xanthe/Xena/Xiënna/Ximena/Xaja.

Cas is really nice! But if you don't want that first letter, then it's out anyway.

My favorite combinations are:
Job, Len and Riv (Idze Valentijn)
Job, Len and Raf (Aaron Fender)
Job, Len and Ela (Lauren Aukje)
Job, Len and Iva (Viènn Amarins)

I think Rox is a nice name, but indeed tricky to combine. Olivia (for me the most beautiful name with an o) seems to me quite similar to Olivier.

The only thing I can think of is: Rox Olga/Oletha Xenia/Xanthe

Also: Job, Len and
Ava (Ava Valerie Anna)
Eva (Eva Vera Amélie)
Evi (Evi Veerle Isolde)
Fee (Fee Emma Elodie)
Ise (Ise Sophia Elena)
Kim (Kim Imke Maria)
Mia (Mia Irisa Annemijn)
Nia (Nia Imara Amber)
Nim (Nim Iris Mariël)
Pip (Pip Isabella Philine)
Tes (Tes Elise Sophia)
Zoë (Zoë Olga Evelijn)

And for a boy: Job, Len and
Art (Art Ruben Tobias)
Bas (Bas Aron Samuel)
Fer (Fer Eden Rafael)
Ian (Ian Axel Nikola)
Ivo (Ivo Victor Otis)
Kaj (Kaj Armin Julian)
Mik (Mik Ivar Kylian)
Ole (Ole Lester Ethan)
Pim (Pim Ilias Marijn)
Raf (Raf Alex Fabian)
Rik (Rik Idris Kelvin)
Sil (Sil Idris Lucas)
Seb (Seb Espen Bastiaan)
Tom (Tom Odin Manuel)
Vic (Vic Isaac Christian)

Rox I don't find very nice with the other names either, I think Rox is a bit more "ordinaire". While I think Job and Len are really nice, stylish names!
I see that you'd rather not have something with an L, but I find Liz/Lizzy nice for a girl and for a boy Seff or written as Seph (so pronounced seff)

How lovely! Congratulations!!
Enjoy it!

Raf Abel Florian is a beautiful name. Job and Len should be ashamed to have such silly names. I can't even pronounce them. Raf sounds really strong and unique. Nice for you guys, it sounds like a household with lots going on.