1. This is a normal procedures for all aproaches and was common even before VNAV. The logic of VNAV won't let you descent below the MCP altitude (pretty smart), so by setting MDA (not airfield elevation, at least with standard Boeing procedures) in the MCP altitude window, you let VNAV transition to final approach logic and once you are 300ft or more below the platform altitude, you can wind it back up to missed approach altitude, and VNAV will continue descending on final approach.
As Denti points out, IAN exists, but it comes with a hefty price as a customer option and not many airlines take it up.
2. Boeing guidance is the same. If windshear is confirmed, then you should delay takeoff or discontinue the approach (FCOM SP 16 has some good stuff in it). However if windshear is only suspected, you can improve aircraft's performance by rotating at the performance-limited Vr (which can be up to 20kts higher than normal Vr), to give you better performance in case that you actually end up in a windshear.
3. Track up is a customer option, that can be only changed by the airline. Personally, I never look at the compass rose below the PFD, and track up is by far superior for most phases of flying, with the odd exception of transitioning to visual part of the landing with high crosswinds, where the runway on the ND will appear straight ahead rather that left/right.