outhouse, don't have a lot of time to answer.. pub calls!!
Anyhow, briefly, autostart does just what it says, start automatically, no fiddling with switches needed... (actually it's an autorelight function)
A RAT would never produce pressurized air. The RAT will only pressurize the GREEN hyrdaulic system, which in turn could run the Emergence GEN. So the RAT can produce Hydraulics or Electricity, No AIR.
The windmilling of the engine would be sufficient to try the initial restart, and at lower levels you could try the APU for APU bleed pressure.
Airbus aknowledges the problem with icing on fan blades, hence the OEB. And it's not an airbus problem, it's a common engine problem. Don't forget that only the cowling of the engine is heated, and the spinner has some kind of a rubber that vibrates to knock of ice in early stages. If you leave the blades turning at a constant (low) RPM, EVERY engine will build up blade ice in moderate or heavy icing conditions.
Hope this answers a few of your questions.
Of to the pub now...
MR8