Everything is in order. I personally use this build at all times. The item build, you want to get all of that asap, in that order preferably. The second archangels staff only get once the first one has fully transformed to its next form because their uniques do not stack, this will get you to 2000 mana once both are done, and will make it so you get an extra 60 AP, 30 for each Seraphs embrace, and with just the first one and the Deathcap you will be doing 600 damage per bomb and once you get the second Seraphs embrace it will boost it a good chunk more.