My guess for the Chaos Dwarfs is that they are probably going to be very similar to dwarfs themselves, but with extra things like bull centaurs (dwarf upper half, bull lower half) and flying demon bulls with lords riding them and 'Lamassu' which are flying mounts that are themselves casters (so a general riding one will be able to cast spells now). They also have spell casters instead of rune smiths and demons called K'aadai that look kind of like Ragnaros from Warcraft.

This might sound like "Hey... aren't they just the dwarfs with none of their weaknesses?" But this is probably going to be balanced by the other thing about the Chaos Dwarfs... there are extremely few of them we're talking a million or 2 total Chaos Dwarfs on the entire planet tops. They are extremely rare. To make up for this they have a huge slave army made up mostly of greenskins with Hobgoblin (human sized goblins that are even more devious to the point where they don't trust other Hobgoblins) as overseers. So their army is probably going to be a handful of dwarfs (either capped like the tomb kings or VERY expensive) and a metric shit ton of enslaved orcs and goblins with a few hobgoblins, but all the non dwarfs have the expendable trait.