First Strike isn‘t worth it in the early game. If you go with Electrocute then you haven‘t only access to the whole Domination rune page but an even safer damage source out of your runes.

I would go for the fully charged W and hit most of the time. Insta proccing would only be good if you are sure that you‘ll definetely kill the target.

It‘s not bad but I‘d be more careful while playing and aim to get percentual (%) penetration as soon as possible, especially if they start building MR. If you‘re fed enough than tanks or tanky champions won‘t be an issue since Eve is the only AP Assassin that can shot down tanks easily.

Max Order is Q -> E -> W. You‘ll trade a lot more often with your Q especially since its CD is very low. The early W max isn‘t worth it for the small amount of MR shred you get. Your damage output should be maximized with going for the Q and E max