Rip Blood only ever hits twice. The initial target gets hit by the (single target Rip Blood plus one of the Blood Splatters while everything else gets hit by the 2 Blood Splatters).
That sounds like a bug, unless you’re constantly going over/under the threshold.
Since you mentioned you’re not sure what to do with Transplant, one thing you might consider (that I think is fun), is picking up Dance of Blood and replacing one of your other skills with Rip Blood. There are a few of things that you could do from there that are potentially beneficial for your build.
Whether or not any of that would be better than what you’re doing now, I don’t know, but it’s worth considering and/or playing around with IMO.
As long as you know that gear isn’t even slightly plausible, so you’ll need to remove at least 1 point from Marrow Shards & Spirit Plague.
Only if there are 3 separate targets. But yes, that & up to 7 detonations (Depravity, Black Mirror) do make for a good nuke.
What exactly is not possible?
It’s extremely unlikely that you’re going to find items with two T7 affixes that you want, let alone being on a weapon and catalyst, and the same bases, that you want. And the chance that you’re ever going to see even a single item drop with any arrangement of three T7 affixes is so close to “never” that it may as well be completely dismissed.
Don’t make plans based on the idea that you’re going to get the theoretically best possible gear. It works in other games, but not in this one.
Having all 4 affixes be t7? Sealing t4 affixes is also improbable rather than impossible. Its fine for the legendaries if the affixes represent what you’d like to see, but you’re unlikely to get a 4lp unique.
I’ve managed to seal t4 affixes already, so it’s doable.
About 4 legendary potential uniques…well the build presented is just a draft, gonna take what I’ll find.
T4 seals. Yip, its possible just unlikely enough not to bank on it. I have a few, but as luck would have it, invariably its when you dont care too much if it seals or not that you get the T4. 
and then the sweat sets in to use the last few FP to make it a really good item.
imho, i wouldnt bank on more than 1lp (maybe 2lp) legendaries - even thats not likely but depends on the particular unique (they all have different lp chances). More than 2lp is likely gonna be on a less op unique that will probably not be build defining anyway.
just managing expectations. the build planner can be a little starry eyed sometimes… Might suggest that @Dammitt adds a special feature that estimates how likely it would be to roll the gear in the planner… Sort of a “are you mad or just lucky” scale. 
It’s a bit hard for me to see the actual purpose of this thread.
You asked for feedback and got plenty. But yet you respond to every post like “don’t care what you say, I know it better”.
Don’t get me wrong. I don’t think you should just brainlessly take every post literally and implemented it into your build. But when you ask for feedback you should think about it, whether it is valid for you or not. Currently it looks like you are kind of offended by responses that criticize your build. It’s not meant that way.
Well, look at the build draft from the 1st post, then the one posted here - do you still claim I’m deaf to feedback?
Yeah, your right. My apologies. It’s just the way I read your last few posts. I maybe misinterpret the tone (since it’s hard to hear the tone on written words).
Sorry. 
I’m trying to locate the names you’ve mentioned, but I can’t. Where are these, exactly?
No problem mate. You, and others just try to help, and I’m grateful even if I don’t follow all the hints and advices.
Btw, I wonder how Lich’s node Soul Maw works exactly. Is it like, assuming no other life leech sources than Lich itself and Soul Maw, some like this:
Life Leech = (1% + 5%) * 1.25 = 7.5%
or it just increases amount of life leeched during 3s period? @Llama8 could you enlighten me?
Dance of Blood is for Transplant. The rest are for Rip Blood.
Soul Maw is a multiplier for your total leech, but your maths is correct. I’m not sure it would have any effect 'cause you’ve got the Hollow Lich passive that converts leech to damage and conversion usually occurs before % modifiers are applied. It would be easy to check though. Soul Maw also isn’t a damage modifier in the normal sense, so maybe it is applied before conversion.
How to check that?
Check how much the % increased damage modifiers on your character sheet change as you add/remove points in Soul Maw. If the just change by 10% per point then the % increased leech modifier doesn’t affect it.
Unfortunately, it doesn’t work - there was just 10% increase of spell damage.
Yeah, that’s what I thought.
How is going the leveling @danklebs ?
Well, current status of the build is
I was lucky to get the belt with 4 legendary potential, and in Soulfire Bastion I’ve found T6 %health belt.
However, while the build works great in general I find it a little tedious to cast Spirit Plague before actually attacking enemies; when I was designing it I though it will be good way to get ward on hit due to multiple hits generated by Bone Splinters, and it is…however, playing it is not that smooth as just simply cast Marrow Shards at anything at the edge of screen. Gotta try something else instead of the plague, either Soul Feast spec’ed into cone AoE without need of a curse, or Rip Blood chain explosion linked to Transplant.