Yes, those are our only confirmed canon half-elves.
Accoreding to, ‘Before the Storm,’ there are so few half-elves on Azeroth that Kalecgos’ visage form is kind of useless for walking around unnoticed.
Considering Kalecgos spends most of his time in Dalaran, and the Silver Covenant is not a negligible portion of the city’s population, if most of it were Half-Elves, then he’d likely have little difficulty going unnoticed.