Do you think that this playstyle can fare on Legendary against the boss enemies, however?

Definitely. Even better, since followers are not affected by the difficulty modifier. I would suggest to put a few more perks in Overdraw though. Your arrows will still stagger, even with Overdraw 1/5, but the damage will be low and you may find the fights taking too long. Overdraw 3/5 should be enough IMO.

The only boss that proved challenging was Karstaag and then again, while the follower is down you still have an option to resort to regular sneak archery to which no enemy in Skyrim has an answer. 

You cannot bring a follower in Apocrypha, though. That's currently the main problem for my "Overhate 2.0" as you dubbed him, the no crafting on Legendary build. And believe it or not a Dremora Lord loses 1:1 to a Lurker (or at least despawns before it can kill it).

That's where Yekef shines  The Fear enchantment on the bow is powerful enough (with bonuses from potions, Ahzidal gear and Seeker of Sorcery) to affect even Lurker Guardians. And there is not enough place in Apocrypha for them to run away. Seekers were actually more problematic for me but manageable with Invisibility and sneak archery 

Sounds good, though it will be a while.  When I have free time write now I'm either writing my blog posts for the Graveknight's Oath or working on a new build. 

I have two that I'm working on right now, and neither is a Bosmer.  But maybe down the road.

Beats me, bro. Maybe I just can't relate since very few of my characters use weapons. As an unarmed combat enthusiast, I eat sleep and breathe glitches. Glitches are my bitches. 

Vaz has released another build?!

This is super cool. I love the concept of being an Illusionist without illusions, and sneak archery is right up my alley anyway.

Also, why not invest in Aspect of Terror? Wouldn't that boost the fear enchant on the bow? And how did you deal with undead?