Saying verbs before nouns

[stopgap]

Now that my son started walking (16 months) and can push to stand unassisted (16.5 months) I've started to wonder a bit about his language development. He's 17 months next week, and I know they all develop differently, yadda yadda etc. etc. but I am concerned that my son still doesn't say mummy or daddy (he said "mamma" once or twice, but that was a long time ago). He pretty much says "dog" consistently, and we've had a couple of other nouns, but nothing consistent. He can point to a lot of things I ask of him and says a few animal noises. He has a very silly sense of humour and "gets" jokes.

His spoken language is almost all verb-related:

What is that?
I like that (usually after nursing)
Over there
I did it
More please
All done

I can't seem to find anything on kids saying verbs before nouns. Does this seem a little odd? (Full disclaimer: he had raging silent reflux, a bizarre one-legged shuffle, arm flaps a lot, hums when he shoves food into his mouth"sensory" issues have been suggested a few timesand so every now and again, parental concern rears its ugly head.)

He can point to lots of thingsanimals, some body parts, various relatives in photosand loves books. Right now he likes The Three Little Pigs and laughs hysterically when the houses get blown down.

The phrases are chunks. I think they're called "big words", right?

He often says "yes" when I ask him a question or shakes his hand (he can't say "no").

No, he hasn't (well, only after birth). Does that count? He has his ears looked inside at each paediatrician visit (last one was fifteen months). He responds to his name the vast majority of the time.

Can someone please tell me about echolalia in toddlers.