Mmmm,
I think the morning star, the arsenic and the Fahrenheit are not really necessary. For me - if I get the upper hand with my scarab deck - I win. But you need time to get the upper hand, so you want to put in things that actually hinder your opponents assault (electrocuter, pulverizer, ..) or make you last longer (Jade staff, Vampire dagger).
as for upgrades: go for the electrum hourglases first - makes your deck faster. Definitely the armors and then perhaps the stiletto and the quintessence.
The blessings are not better than an armor but worse in this deck, since you need to make the scarabs better. I'd exchange them for more armors or quintessence.
And a nymph? Awesome you got one - but it costs a lot of aether.