Baby passport photo - open mouth?

I’m a NZ expat in the US with a 7-month-old who needs a NZ passport. His default state of existence is mouth open, and he won’t really close his mouth on request.

I’ve captured some mostly acceptable photos: neutral expressions, head straight, eyes open, looking at the camera, plain background.. it’s just his mouth.

How lenient is the New Zealand Passports office about baby photos? I note the baby section of their How to take a passport photo page doesn’t reiterate closed mouth, which is promising.

Anyone from DIA lurking here who wants to reassure me I’ll be fine? Applying from overseas I don’t really want to get this wrong.

(Not quite prepared to post my child’s image publicly on Reddit, but I’d DM the right person if they’re an expert.)