Out of these I would say Jungo is the best.

Skeelz are very good too although I'd personally use Chiara or Andy Ld over Zeke.

Mono-Nightmare looks great although lacking in power making some match-ups very tough.

Mono-Pcats look find, although they would obviously suffer against SoA or SoB match-ups.

Mono-Roots is usable but I'm not sure if it's the best choice as of now.

I say run either
Nightmare-cats half

Glorg Pan Artus kenny
Diana Clover Lucy Muze

Or Jungo/cats

Askai Jean Scopica Nyema
Diana Clover Muze Lucy

You don't need two "Double-stop" but a round-winning card. I suggest replacing Dieter with Edwin. Replacing Eadh with Mawpin may also be wise. Mawpin is a 3* with its ability activated.

Half-decking is easier, IMO. In Mono you will find that each clan has a weakness of some kind... Too many low-damage draws vs SoB or SoA, not enough round-winning power, etc. Playing with 2 clans offers the opportunity to create a deck with more well-rounded draws. However, it's best if your cards can survive without bonus.

P.S. Phyllis is a 3* in a 2*s body that doesn't require revenge. Compare to Praxie (she may not have min 0 like he does, but the power difference and higher min is compensated by the more versatile SoB, which also protects ability vs GHEIST and Roots.)

Phyllis is a really nice 2* but its utility drops towards the end of the battle (So both Mawpin and Phyllis have a certain extent of restriction on their usage, maybe Phyllis has less). But I agree with ghelas that she is a really good choice for a Nightmare ELO deck. It's a matter of preference.