I don't care about Nyx because she isn't my style of warframe but the changes for her look ok to me.
Titania is a different story. I love Titania in her current form, I enjoy razorwing and how it functions and I adore the buff to lantern and the vacuum addition to razerwing is going to make her feel SO much more comfortable to play I think. Having said that I don't think you are doing enough with the aura's. Yes the ability to stack them up to max with one cast is a welcome change but as so many others have stated before me, the buffs are very underwhelming and could be better.
Thorns is gained from melee enemies and is useless for obvious reasons, damage reflect in this game is pointless with armor reduction and others have run the numbers in this thread to prove it so I don't need to say more I think. I would like to see it become a small buff effect similar to how octavia gets small buffs for doing specific actions in time to music. Tribute a melee enemy, get a small buff to melee damage or attack speed. It doesn't have to be large but it would be far more useful of an ability than damage reflection especially in aura form for the rest of the team.
Dust I think isn't "as" useless especially when you consider the accuracy debuff aura mod for corpus. I come from World of Warcraft where tanking meant damage mitigation and I think people underestimate the use of straight damage mitigation. Having said that it is still underwhelming for one reason and one reason only. Damage mitigation doesn't mean anything if the enemy is dealing enough damage to one shot you with that one bullet in 10 that actually lands. Damage reduction is a far more effective stat in the current state of the game for defensive purposes which places armor and damage reduction abilities head and shoulders above accuracy debuff. If enemies couldn't simply one shot you at high levels this aura might be more useful but that isn't the case. I would even be ok with this getting flipped into "allies get more accuracy" which some might argue with me is still not as useful but I would counter with "take any full auto weapon into the sim at a range of 40m and tell me how useful accuracy can be afterwards. Course we could just slap multishot to primary or something on it and call it a day.
Entangle is the only one I see as being somewhat ok in its current form albeit only somewhat. The range at which the slow is applied is pitifully small to any but melee attack range and isn't effected by mods so that kinda sucks but its still useful. So I'll leave it there.
Full Moon....ugh....companion damage. I am never a fan of any mechanic that places damage and its application outside of my control. In WoW and similar games where you have AI controlled allies there is usually always a way to tell your companion "kill this thing" and if I had that ability I would be 100% ok with this aura because I would combine it with a team of Khora's and wreck high value targets with insane companion damage probably using kavaats. But thats not how this game works and because I can't give my pet orders yet (DE PLEASE ADD THIS) this feels super underwhelming. Bottom lining it though, I would rather have the ability to tell my pet what to do than have this particular aura reworked and the addition of it adding damage to the butterflies as well I think increases the use a fair amount because those things can be rather vicious anyway.
I would like to close this rant/suggestion box with a note. I view Titania's role in the team like a fighter jet in the air force providing support for ground troops, I would like to see more creative buffs than just flat damage in these auras (enemy highlighting behind walls would be a freaking awesome aura ability that I just thought of) and I would love to see these auras reflect that role a bit better, providing some sort of buff to the team that feels more significant and worth taking the time to cast the ability for. I thank you for your time and consideration in reading this :) and thank you to the development team for the work that you do.