It's 15 years since I was an F/E on the Electra.
IIRC we started 4 on external air and then disconnected the air and GPU with the engine in LSGI. When the oil temp was above zero we upshifted to HSGI and used crossbleed to start 3,2 & 1.
After an incident when a dozy F/E (not me) selected no.3 first by mistake and an equally dozy ground guy was hit by no.3 prop as it started to turn, we changed our procedure to only open the bleed valves as they were required for each engine.
Hope this helps.
HAPPY NEW YEAR.