Trimming into an airspeed with a gliding airbus is simple : just do nothing and the aircraft will maintain its pitch angle, speed will then progressively stabilize at the speed which corresponds to this pitch angle.
No, it won't. Hands off, it'll maintain its current flight path until the speed reaches Valphaprot, then a nose down term will be introduced.
How did starting the APU retain normal flight control law? I haven't read the report but loss of G & Y HYD system will result in ALT LAW.
I believe at least one engine continued to run sub-idle, but sufficient to provide hydraulic pressure.