Two things - first things first, thread related:
The aircraft was BB-1473, so did have electro-hydraulic gear.
Any ideas, what could cause a "major electrical system failure" on a King Air 200?
A scenario often presented in training is the blown current limiter, followed by loss of a generator - a multiple failure, but has occurred in the past. In that scenario, the battery supplies power to one generator bus, which may only last so long before a battery charge annunciation occurs with a Ni-Cad battery installed. The battery charge light would be a cause for alarm, due to the potential of a thermal runaway.
Loss of an inverter, and not following the memory item, would cause a loss of AC. AC powers EFIS instruments, autopilot, gyros and avionics. This in of itself wouldn't lead to a gear issue, but significantly increases the workload of the crew. When I'm rushed, I'm more likely to make mistakes, or omissions.
SOPs..
Switching auto ignition on or off in flight is not really a sign of poor SOPs - although I'm not at all familiar to the reference made. I flew for a King Air operator that insisted the auto ignitions be turned off during the climb checklist, and turned back on during the before landing checklist. Auto ignitions were to be turned on in icing conditions, turbulence or wind-shear, and moderate or heavier precipitation. The theory was that too many ignitor-boxes had been replaced from them being left on (all the time), with the power being brought to idle etc., so the operator wrote their SOP as above. Also, the manufacturer doesn't require the auto ignitions be on during the entire flight, on the King Air 200 and earlier models. The operator has a fleet of King Airs, of all types, heavily used (800-1200 hours per year per airframe) and has been in business for about 30 years. That was part of their SOP, and everyone followed them.
Recently, however, I have been flying with an operator that leaves them on during the entire flight, and doesn't care for the cost of replacing them if they fail, as the owner can well afford the aircraft, or to charter an aircraft if need be and the King Air is lightly used. One less checklist item keeps it simple, so I'm all for that.