Interesting, so at least one FD is still required? From the FCOM of a german airline:
IAN may be used with the flight director, single autopilot, or flown with raw data. The procedure turn, initial approach, and final approach are similar to the ILS.
Which most of us used to fly most IAN approaches in "raw data" without any flight director help. Same as we did for most ILS and GLS approaches. When we phased out the 737 we sorely missed that feature on the A320, which theoretically could have it with FLS, but i have not seen a FLS equipped A320 in the wild despite flying it for numerous operators, unlike IAN which has been standard for since 2005 or so, same as GLS.