Hey Euthanize4Life. Not claiming what I say to be better than what you have posted but im just gonna say what I think you could do better.

Masteries: Why finish in the Ferocity Tree? You get deathfire touch however that doesnt work for evelynn to much. Deathfire touch does dmg over time whereas if you finished and got your keystone in the cunning tree then you could get Thunderlords which buffs evelynn and give her very strong burst early due to her q being low cooldown and being able to proc it alot. Another thing in the ferocity tree you say that you should use Natural Talent which gives evelynn very little late game scaling but say she should use Vampirism over Oppresor. Oppresor works very well with evelynn as soon as she gets rylais because withe her q anyone shes fighting will be slows so you will always have +2.5% dmg.

Items: I think your build is extremeley viable and what most people should use (build around) on evelynn. I think Rylais should be second item and be prioritized over completed boots. Rylais is large power spike (slow, +2.5% dmg). Sorcs shoes are good but i think cdr boots are better for offensive just because they are SO cheap right now, but i reccomend going with defensive boots (tabi, mercs).

Starting Items: I think this is the worst part of your guide. Starting with either talisman or machete works HOWEVER evelynn has plenty of mana sustain with her passive so if you choose machete you wont have mana issues in long run and you can get too full health from less than half just by auto attacking the scuttle crab with you e (for atk speed). For your first start you should always get health potions. Reffilable pot just isnt enoough.

Check out my guide if you think any of my points make sense. I have lots of strategies for early game and am uploading videos soon.

Thanks,
Imnotjon

This is my first proper guide. I'll be continuing to work on it and support it, as well as update it with changes I find to be improving my game. Evelynn is my favorite champ, and I play her in most matches.