Not sure if you ever got it work with the steering wheels controls. But with mine (2011 E90 not sure if it makes a difference) I deleted all my songs like you. This fixed the switching to the music app. Now I plug in my phone when the song is paused. Then select ipod on the headunit. It starts immediately and I can use the steering wheel controls. You also have to select the random button on the headunit for the steering wheel controls to work for some reason.
2013 F30 335i /// Glacier Silver Metallic /// Coral Red
ZSL // ZPP // ZDA // ZPK // ZLP // ZTP // 2TB
Velgen VMB5 19x9 19x10.5 // JB4 // MPE // Injen Intake
Retired: '11 E90 328i Space Gray