When Mark was testing MDL-51247 in voice over on mac, it was suggesting some unusual key combinations to open the suggestions list and move through the selected items.

Control-Option-Space to open the suggestions or Control-Option-Left and Control-Option-Right to move through them.

The left/right ones sound ugly for RTL languages - we need to investigate if voice-over is supposed to translate these to some standard event or we are expected to code in support for them.