1. Surely that's a problem for the ground crew to solve.
2. If you will be using the
service interphone system you'll need to transmit via CAB. I've never done this, comms were always via the flight crew interphone system to the ground handler, never directly to the engineer.
3. It take me longer to explain than for you to read the apropriate chapter in FCOM
4. 'Select APU bleed ON just before engine shutdown'. A question of interpretation. I agree with you that 89% of the crews do it too soon.
5. FCOM explains states this.
6. No idea, never heard of this.
7. With GS mini working as it should you will land at Vapp so GS mini is not going to save you from a Vapp which is too low. GS mini doesn't 'cater for speed reduction'. Read the FCTM, it clearly explains GS mini.