To stick to the topic.
The B747 WILL have 3000psi with all engs windmilling down to about 160kts.
There is no possibility of any 115VAC with engs windmilling.
There is no possibility of any ADP with engs windmilling.
Gear and flaps will be available, albeit at reduced rates, with all engs windmilling. This will not result in loss of control - system 2 & 3 hydraulics can handle flight controls while systems 1 & 4 are busy.