As far as i know, there is no benefit for Green Dragon Bloodline at this point during EA ...
SInce damage boost you get at level 6.
As for items ...
Robe is curently buged and boost even damage you give to yourself ...
And Staff of Crones give wielder damage for every use aswell ...
So if you really want to make this build working, i recomend to also find Ring of Poison resistance.
Problem is its no longer even interesting once you reach level 5 ... bcs at that point, your cantrips will be potentialy 2-4 points stronger than Ray of Sickness (item spells cant be upcasted)
So ... nope, basicaly its not worth it in curent state of game.

//Edit:
At best you can make it work for your 1-4 levels ... but even that is quite short period of time.
I remember that one time i played Poison Sorcerer ... and it was quite fun and felt really strong, but back in those days level 4 was our maximum ...
Anyway i used:
https://baldursgate3.wiki.fextralife.com/Staff+of+Crones - To get Ray of Sickness, my main (and often only) offensive spell.
https://baldursgate3.wiki.fextralife.com/Poisoner's+Robe - To boost that damage (no surprise here i suppose)
https://baldursgate3.wiki.fextralife.com/Ring+of+Poison+Resistance - Very important item, it halves damage you get from your own attacks ...
https://baldursgate3.wiki.fextralife.com/Boots+of+Aid+and+Comfort - To get extra HP that can help me soak that im harming myself as i attack.
https://baldursgate3.wiki.fextralife.com/Gloves+of+Power - Bcs combined with Ray of Sickness, my enemies were litteraly unable to hit anything.
https://baldursgate3.wiki.fextralife.com/Ilmater's+Aid - To even futher boost my damage outcome.

There was no problem staying half dead, as i kept damaging myself.
https://baldursgate3.wiki.fextralife.com/Emerald+Ring - Just to be able to attack sooner.

Then, my whole tactic was to turn all my spellslots into Sorcery Points ... and twin every single cast of Ray of Sickess ... usualy killed two enemies per turn.
