Hi,
So, that looks identical to the head unit in my 2014 Hybrid - does yours have the 18 speaker sound system as well? If it has, I am (as sure as I can be) that you don't need the MOST adapter in the second picture (more for the OP's info than you Hardi) - that's for alternated HU's that don't have the MOST control built in (i.e. an Android HU).
From another thread on here on no sound issues, I think the top connector next to the one labelled FM 75 ohm with the 4 round co-ax type is the MOST audio bus that connects the amplifier and the rear screen sound - this is a loop system so if there are any breaks in it the audio doesn't work.
Sorry no idea on the steering wheel controls, but I may have in a few weeks when my Android HU arrives with all the cables....