You've got some pretty good lists there. Nicely done. Now all comments below are just how I would play the lists or changes I would make. Take them with a pinch of salt.
Deneghra1: First your comments about the arc nodes. They are there to allow you to get her spells on targets so that your troops can do the killing. Two should be sufficient for your needs. What I used to do with them is run them first turn straight ahead. Don't. 10" if going second, or up to 13" if first. Reduce those values if the enemies shooting worries you (retribution's Ravyn and some Cygnar/Legion stuff). Use one arc node at a time by moving it up into spell range and cast through it. Keep the other one back till the next turn. They are arc nodes first, offensive pieces second.
The Deathripper is awesome in combat but to be so it requires focus, something which Deneghra has little to spare as she's wanting to cast spell. If you can get a few focus on it, especially on feat turn, it will be able to hit on the first attack then the others hit automatically, all at POW 13 (+2 for feat). The Defiler's spray is less likely to hit at
RAT 5 vs FOCUS 7 but has more POW. It should be after slightly different targets, but not by much.
The deathjack is an interesting one. It's perfect for a 35pt game, any less and it's too many points tied up in a single model. Focus efficient and able to cast Denghra's spells as well it'll do better here than with Asphyxious. Though I've been having good luck with Nightmare instead of Deathjack. The Prey bonus means he's hitting as hard as the Deathjack at a higher
MAT. Unfortunately you are losing out on the spell casting. Deathjack gives you a focus efficient heavy, that can heal itself and cast spells. Nightmare gives you a stealthed heavy, that can go ghostly without help (but use the skarlock if you need it to) and has a very high threat range against the enemy. One game I preyed a carnivian as those things with assault can really threaten the squishy Deneghra. My opponent kept it at the back of his army most of the game. That's a fair trade as I had to use nightmare to kill the last thing in the zone for me to win.
One last thing, your bane thralls will slow up your list. Make sure your other stuff doesn't get too far ahead.
So, if you keep with the deathjack I would either downgrade the defiler to a deathripper and put in Bile Thralls (min) to clear infantry like no other. Or add a second Warwitch Siren and Gorman Di Wulfe (great solo). If nightmare then you'll have 6/7 points spare (defiler/deathripper downgrade). Add in the bile thralls and either a necrotech(or machine wraith) or Warwitch siren.
Hope that makes sense.
Asphyxious (assuming prime/1 from your idea of 5 POW 14's)
Now I'm guessing you haven't played much with him so I'll just run through a couple of things. His weakness is that he doesn't help your army hit things. So watch out for high defence things. You're right about one of his assassination threats but I don't think it's his main one. Firstly if he hits in melee then the rest of his attacks will hit automatically. Say you have saved his feat for this then that thing should be dead and you can teleport away afterwards. Secondly, against a squishy (
ARM 15 or less) caster I would be attempting to get an arc node to be within 4". The thing with AOEs is that they can only scatter half the distance between the target (or max range whichever is smallest) and a 2" move will not deviate off a small base. ( I hope that makes sense). What all that maths means is that Breath of Corruption will not scatter off the target if your point of origin is within 4". And Breath of Corruption has the special rule that deals a POW 12 to everything hit, it's not halved like a normal AOE. So that's 4 auto hitting POW 12s, two of which will be boosted. Similar to the hellfire route but a surer way of killing the squishy casters.
Anyways, on to the list you have. Tartarus is very good to help the bane thralls hit so good choice there. Three arc nodes is slightly over kill but worth it as it'll force the enemy to play as if a spell assassination is coming next turn, no matter if it is or not. It's the Withershadow Combine that is an interesting choice. I hadn't really thought of them as a useful addition to Asphyxious but now I'm seeing that a free upkeep of Scything Touch is great. Just remember the puppet master ability. Something I'm always forgetting with them. It'll really help with the assassination run as it'll reduce the chances of that double 1 for damage.
Basically use the list as is, and add in another Warwitch Siren for running the arc nodes. Also add Saxon Orrik. He'll give the bane thralls or asphyxious pathfinder as that's the other weakness of this list.
Hope this helps and ask if I've been unclear in any place.
