B738HT:
1. It depends on why you are using the TE ALTN system. If it is for a flap problem then I assume HYD B is available. You ARM the ALTN flap system and then momentarily select the electric flap switch down. The LED system goes directly to FULL EXT position. You have disconnected the HYD B from all the flaps and connected LED to SBY & TE to electric. The LED's cannot be retracted via the ALTN system. If you have HYD B available, and close the ALTN flap ARM switch you can retract the LED's depending on where you position the flap lever. Of course, if you move the flap lever it will also command the TE flaps to move.
2. The LOSS of THRUST on Both Engines is a very different scenario to an Engine Inflight Start. With total loss you want a recovery ASAP so speed (windmill) and Ignitors are your priority. Engine & FADEC buffs will know more, but I suspect that a high speed windmill start might be more successful with TL commanding a little more fuel than idle. I'm not an engineer and welcome the real reason.