[BUILD HELP] Help me out with FP HP Based Shadow!

Guys, trying to make a build viable for HC, so i wanna know what would u change to make the best out of it FOR HC (point is i dont wanna die, and if i have to sacrifice dmg so be it).

Completed build: http://www.pathofexile.com/passive-skill-tree/AAAAAgYAAv4DHgSzBUIHHgdjDF8OSBEPEZYUsBXnFkAWbxa_F1QaOBynHRQfQSKBJKomlScvLJwwlzbpN4E5UjmKOlg8LUGWQsNFfEbXSVFMLUyzTP9QMFKyU6VT1FVLVcZWSlgHXfJfKmHiY0NknWaeaPJwUnDVcYVzs3RVeC-CHoKbg9uFfYhCidOMNo2CjjyOZI9Gj_qQVZUul5eboZ6hnwGiAKyYrrOvbLFCtvq3Prw3wBrAZsHFxq7LvdD10eTYvdsL217fhOFz41bjauTr5oHr5Ov17BjsOO0g8B_wa_DV8h3zEfem99f60v4K

Thing would be to just bypass dmg while leveling and get all the hp and armor possible while getting some points (just some) on dmg related nodes.

Skill Gems:

Freezing Pulse - LMP - Spell Echo - Power Charge on Crit - Life Leech
Frostbite - Assassin's Mark
Enduring Cry - Immortal Call - CWDT - Increased Duration

Questions:
I dont know where to go with auras, which ones should i get and level?
Is this truly viable for end-game content?
Any suggestions or changes u would make?

Ty in advance!

I would strongly suggest taking vaal pact to deal with reflect (you come very close to it anyways).

You are also low on mana regen, specifically if you want to run arctic armour.

For buffs/auras I would suggest, herald of ice, herald of thunder, clarity, and aa. If you do not use cloak of defiance you could also add a purity in there, as unreserved mana will be a bit low.

For supports I would recommend gmp-echo-cold pen-life leech. Penetration is a really huge damage boost, especially when dealing with overcapped resist and curse immune enemies. Charges can be generated via other methods, but I suppose that is also personal preference.

Good luck!