Specifically I was wondering about the Twilight Tormentor/Daedric Prey/Storm Atronarch after the synergy. I don't think Clannfear would be effective since it does physical damage. Their bonuses add up to 125% of their damage after all effects take in, but does it make effective dps? I want to play a character like this but I don't know if it's worth investing in things like Necropotence and morphs.
I really like the looks of a lot of this. Since you seem to be familiar with this, do you feel like there's any justification to use Daedric Prey or the Storm Atro?
On live, currently, there's no reason to use Prey. The Tormentor doesn't add enough damage to be worth the button press vs an instant ability, and it only offers that option for half the fight. The Atronach does benefit from it, but unless you're in a single target situation where its ability to shock at range is useful, Meteor is cheaper and higher damage. The Volatile Scamp's pulse doesn't benefit from prey.
A Summoner build that works for dungeons right now (DPS) is to simply take the BSW/Ilambris meta, replace bsw for Necropotence, and replace Velo Curse/ Mage's Wrath with Volatile familiar. It gains AoE damage at the cost of single target burst, most suited to pledges or extended trash pulls in trials.
Volatile Familiar/Greater Storm Atronach/Daedric Prey is very strong on the PTS currently. If the changes make it into Live you will start seeing more high level players using Familiars.