Love the item build!

i think it would be a good idea to link some of the runes or other spells if you don't know how then go to jhoijhoi guide for making a guide xD It has everything you will need to know about how to make a guide. xD. and you need to BBcode items like Void Staff

I never really tried maxing Fox-Fire first bot i gezz it works. but yeah it's also awesome to towerdive with when enemy are low on health just ult in, foxfire, let it do some dmg one more ult before ulting out of tower range. you are sure you will not miss as if you used q or e.
but mostly it depends on who the enemy is if it's someone like teemo it's important to get the foxfire first as it shows where teemo is. (I hate when ihe stands in the middle of the lane just chilling.) Ahri is a perfect counter for him xD

I would not take Dorans ring as first item, get boots instead, then you can change your quintesses to AP to make up for the AP loss from not buying Dorans ring and if you think that you loss the 100+ health from not buying dorans ring then you think wrong 3 potions = 450 hp. you will get more stats this way. the only loss is the mana regen but if you have a good jungler he would probably give you blue when it comes for the 2nd time. xD