Disclaimer : I know this isnt answering the question, there is no
RAW answer, as others have already said. Take this as a guideline how to house rule it, until
GW answers this in a
FAQ. Mob up is about the same as consolidate squads.
Q: When using the Mob Up Stratagem, do any of the rules
effects that were being applied to the selected units get applied
to the merged unit? For example, if one unit had Advanced or
Fallen Back, does the merged unit count as having Advanced or
Fallen Back, or if one unit is under the effect of a psychic power,
is the merged unit still under its effects?
A: Yes, each rule effect that was being applied to each of
the selected units is applied to the merged unit.
Q: What happens when the Mob Up Stratagem is used to merge
a <Clan> Infantry unit that has a Clan Kultur with a
<Clan> Infantry unit without a Clan Kultur?
A: The merged unit would not have a Clan Kultur. The
merged unit only has a Clan Kultur if the selected units
both had it.