Top panel is really easy to remove, just buy yourself a decent set of plastic trim removal tools. There is one particular tool that's perfect for the job, can't link a photo as I'm in France at the moment!
Yes you can app mode the garmin app from an iPhone, however beware the app is £35 then you have to make another £35 in app purchase for the app mode. It's very expensive and I decided not to bother, shame as it would be quite cool.
My mic is stuck to the area by the reading lights, works very well, however I'm tempted to dismantle it and try to hide it behind the little grill up there.
EQ has 5-6 preset modes then there is a full custom mode, to be honest I've not experimented, I use Rock most of the time.