What skeletons can a Beckoner summon? They are shorter than an Orlan. No, even shorter, look at one of them near Vela:

 

 

Are they baby skeletons? Maybe the hollowborn are back for revenge?

Scaled whatever skeletons base chanters summon probably. Remember that those are not really some kiths skeletons, but fragments of souls of the surroundings that take that form. Guess beckoners get the souls to take the form they want faster so they gather with the closer fragments forming a lot of smaller invocations. Or something like that.