Chaos Armour? Is this the same armour as the Warriors of Chaos? I.e. it welds onto the skin and cannot be taken off.
That's the stuff, gifted by the Chaos Gods.
BC herd? You’ve used herd and pack, makes them sound too much like cattle.
That was my intent. If folks think it sucks, I can be convinced to change it.
Blunderbuss isn’t great, but balanced
Need they be better? As they are a rank & file unit, we obviously don't want them too OTT. Perhaps S4 or AP with an appropriate increase in points?
Boar Centaurs are barely sentient? Sentient means can react to the outside world (my understanding of it anyway). So barely sentient means they must be the most dumb animals in the Warhammer world.
As dealt with earlier, Sentience is conscious self-awareness. "I think therefore I am" is a sentient statement.
To become a Chieftain, a Hobgoblin needs three things: luck, a large nose, and the ability to heard cats. ???? Explain

Yes, I'm very happy with that quote. And I do believe that commanding Hobgoblins will, as the saying goes, be "like herding cats".
‘Rules lawyer’ says: Blessed Visage: The Character has the lower quarters of a Bull Centaur. Gain +3 Movement. You may not take a mount.
So can a BC lord or hero have this upgrade? Logic says no, rules say yes.
Well, it says "may not be taken by Bull Centaurs", and they are BCs so the rules say "no"
High Priest of Hashut – I’d give him an option for a great weapon.
I've given him the Temple Staff instead. The idea is that the three "pillars" of CD society each have a slightly different selection of weapons to add character.
I’d drop the points cost from the stats for each unit in the list, its unnecessary repetition. Just put it above, and any additional points for upgrading command etc put below (as you did)
This is a lay-out artefact, part of the "prettying up" I need to do.
Engineer Lodge. Repeating pistols would come out at 15 pts per model..? IMO a CD with a brace of pistols should be 12pts.
Err, 11 by the figures I have here. I can put it up a point.
Acolytes. I’d change the Priest name, too confusing with the Hero. Too many options IMO. I’d give them 3 cults to choose from. Fluffwise some cults would be bigger than others, hence being seen more often on the battlefield. I’d increase their base cost to 9, maybe even 10 with MR(1).
Fair point, but which Cults do we keep?
Boar Centaurs and Wolf Riders is a very fast CD list, even though neither count towards core. Not sure I’d give them additional hand weapons as an option.
This would also tone down the gits, which is no bad thing really.
Immortals for 24 points (before weapons!)!?!?!? Make them 12 points. Paragon I’d make +12 pts.
I'd actually changed this to 13 pts earlier, but it didn't save. This was done via a comparison to Iron Breakers & Hammers in the dwarf book.
Bull Centaur. 20pts per model IMO. You have to pay for the privilege of speed.
Fair Enough.
Is the Juggernaut a mobile weapons platform? Or some sort of sentient chariot? Is it a warmachine? You need to clarify whether it needs crew (i.e. a Boar Centaur). Its confusing things putting the bolt thrower in the same entry as the juggernaut. If you really want this create a separate special choice of a bolt thrower mounted on a juggernaut (which IMO shouldn’t be pushed by anything).
The CD Juggernaut is the huge siege-tower thing, isn't it?
War Engine: WAY too confusing, and unnecessarily complicated. IMO you can’t combine that many options. Drop the Death Rocket, move the Earthshaker to Rare. Basically make the unit only for swivel guns, possibly treating them the same as war rocket teams (2 models per base etc).
A valid point. I've obviously been reading too many 40K Codices.
Order of the Bull Guard. Fluff confusion here, as an Order would be like 1000 of them etc? I’d make this entry unit size 1+. Give them the same profile as the Immortals (changing the name though). You need to change the name of either these mounts or the Lord’s one, otherwise the riders could be 1+ armour save, unless that is what you wanted? I’d also make the mounts Strength 5. Put the base size on here.
The intent was for these to be cavalry, and heavy, if slow cavalry at that.
1+ unit size would be contary to established Warhammer principals for cav.
They effectively have barding built in. If this is too confusing, I'll just make every single one barded and have done 
With the naming, has anyone a better name for a large bull-mount than Taurus, in order to avoid confusion?
Chaos Armour or shield upgrade on a Taurus is 2+ Armour. both is 1+ armour, but keep in mind these are then 46 point models!
My biggest problem with the list itself is the level of speed. Speed is the single most important factor for balancing the CD list IMO. With the Boar Centaurs, Bull Centaurs, Wolf Riders and Taurus riders you have a very fast list.
True. This is why I barred Bull Guard from Marching, making them effectively fast on the charge only. these are also an expensive Elite unit. If it's still a problem, we can slow them a touch.
With no good way to boost the Ld of the Boar Centaurs, their Stupidity should slow them down, but again, these can be tweaked.
The way its been written needs to be cleared up. You have a lot of fluff and name confusions. Take another look at list and rename as necessary so that no name is used twice, anywhere. You will then need to update the special rules and fluff descriptions.
Easily done
Create a separate fluff profile for everything, including mounts. I.e. you’ve written a combined rules and mini description for all the Warrior Brethern. Split this off into clearly defined areas, and include the profile for each of them underneath. The Warrior Bretheren is the name of a Core unit, so it can't be a header for the section.
You see, here I've been mimicking the format of the official books. If it's not working without the advanced formatting, I can re-jig.
Overall I like several parts of your list. The Obelisk idea (although IMO the wrong name), is very interesting and worth developing. I must admit when I read ‘Warrior Brethren’ I was hoping for something like the Black Templars…
Sorry to disappoint. People seem to like the Obelisks. Has anyone a better name for them?
High Priest - Gar! Should always be Ld10! Points look wrong
Wrong as in too high or two low?
And how would you adjust them with Ld10?