Facing the wind he pinched the sign, said a spell over to himself, shook himself and changed, and what he changed into was the very likeness of the Little Borer of the Wind.

模樣 is the pattern or likeness, with 模 as mú — the second of this chapter's three, and the frame that carries it is consulted by nothing during the work, so it has to be forced each time.

He turned on his heel, went straight back the way he had come and looked for the cave, to spy out the true state of the three old demons.

拽回步 has 拽 as yè, the corpus reading at all eight of its sealed sites. 虛實 is empty-and-solid, the paired word for the real state of an enemy — a term straight out of the military treatises, where knowing that about an opponent is the whole of intelligence.

And this is the very thing:

這正是 is the teller's cue that a couplet is coming. Three characters, and they are the last such cue in the chapter.

A thousand kinds of transformation, the Handsome Monkey King; ten thousand ways of shifting, and true ability in them all!

A parallel couplet, seven and seven — matched item for item, 千般 against 萬樣, transformation against shifting, and the two names at the ends. 騰那 is to vault and shift, with 那 as nuó. The two line-endings do not rhyme and are not meant to: a couplet of this kind asks for matched grammar and contrasting tone, not a rhyme.