You can have a single-phase circuit tapped from a three-phase supply either by connected phase-to-phase, or phase-to-neutral.
The breaker needs to open all ungrounded conductors, so with a 3-ph wye system a phase-to-phase load needs a 2-pole C/B, while a phase-to-neutral load needs only a single-pole, as you've stated.
The only cases that might want adding to your list would be something like a corner-grounded 240V delta, where one of the phases is actually grounded.