I've got a Halfling Rogue (Swashbuckler who selected Kukuris), and eventually planned on getting Desperate Swing (for the +4 confirm with crits while fighting defensively). I was wondering if that +4 stacked with Critical Focus?
Should do. It's an untyped bonus, and it doesn't have the usual text stating it doesn't stack with critical focus (which appears on every other similar ability I've seen).