Unlike how the principal migrant belongs to various sub-categories (ICT-ST, ICT-LT, Graduate Trainee, Skills transfer, shortage, General, etc.) within a category (Tier 2), a dependant belongs to just one category "PBS dependant". So, Tier 2 (ICT) dependant is no different from Tier 2 (General) dependant!
A dependant's leave relies on the leave of the principal migrant, and not on the principal migrant's employer / sponsor / employment.
There is no requirement in the immigration rules (
319C) to suggest that the dependant must make a new leave to remain application at the same time when the principal migrant is switching categories (e.g. - from Tier 2 ICT to Tier 2 G).
A dependant's eligibility to settlement relies on the eligibility of the principal migrant for settlement and the time spent in UK as a "dependant of the same principal migrant (i.e. - same person)". The immigration rules (
319E) do not state anything about the dependant having spent a given period of time in a specific sub-category (ICT, General, etc.) of Tier 2 dependant leave to be eligible for settlement.
IMHO ....