My first thought when looking at your build was that your OA total was too low (1700, when it should probably be mid 2000s, minimum) and your DA total was higher than needed.
My second thought was that a blight fiend companion is probably your best pet companion because it’s a decent tank, it’ll take aggro, it can CC, and it can debuff mobs for you. And yet, that’s the only pet you’re not taking.
Also, a cadence / deadly momentum build could work really well with reaping strike by ensuring you get good, strong infusions of life from ADCtH. Having a good offense can be good defense when you have strong life returns from reaping strike (and other sources, no doubt). You could perhaps even go for a 2H scythe to maximize healing from ADCtH, as long as you can also organize resists.
After switching to the biggest, nastiest 2H scythe you can find, consider moving those shield mastery points into cadence and deadly momentum. Then, find some more attack speed and crush all those inferior beings beneath your heel, like a good death knight. 
In more general terms, perhaps you would enjoy “summon and forget” pets, rather than trying to micromanage pet buff skills while engaging in melee. Your pets can do some damage and serve as distractions for enemies, rather than as primary damage sources. I don’t know if the revenant constellation raise dead celestial is worth it or not these days (I found it mildly lacking, but not terrible, on an earlier dual pistols build; perhaps it would work better while in melee). Blight fiend + raise dead skeletons might give you the “hybrid” feel you’re after, while being useful in-game.
Also, consider getting the Rattosh constellation because you have so much vit damage (after conversion), and yet vit damage probably isn’t built up enough to function well in ultimate difficulty without a hefty dose of resistance reduction. But, from what I can tell you only have resist reduction from one source, in the build given.