Few things.

I wouldn't get a Faerie charm as a starter item. So far I hear that 3 stealth wards + 1 vision ward + 5 pots + Warding Totem is best (krepo said so anyway). Biscuit of rej doesn't exist anymore and nor does explorer ward. I'd change the Ionian's into Mobility boots as they allow faster warding and dewarding and it's the closest thing to an escape you'll have. You shouldn't list your entire build in "Core" as core is meant to be the couple items you get no matter what happens in a game and I consider Zeke's, Locket and Mikael's all to be situational. I wouldn't get both Athene's and Mikael's as they both build from chalice and you getting either will provide you with enough mana anyway. If you want AP get something else instead.
I suggest getting HP quints. While AP is always nice HP is invaluable in bot lane and especially so on squishy supports like Sona. I think your guide is nice but perhaps a bit short. Would like to see it expanded. You should add a Gameplay chapter, an Items chapter and you should write in the Rnes and Masteries chapters more. Need ignite in Spells chapter. You're meant to explain your choices in those chapters.

Good luck with your guide, feel free t message me if you make some changes and want some feedback or something :)