Unknown call - Alaka'i Swamp, Kaua'i, Hawai'i (1 Viewer)

Had a grand old time on Kaua'i this past week. Struggling with placing a call I recorded while hiking through the Pihea trail to the Alaka'i Swamp. I heard at least 2 (possibly 3) individuals consistently repeating this call to one another. I got a glimpse of one of them - a small-to-medium, totally backlit songbird flitting out of view before I could get any real look at it.

Beware your ears turning speakers up - I talk loudly near the mic around 35 second mark. Apologies for the cursing! :eek!:

Thoughts?

Local Hawai'ian expert and author Jim Denny helped point me in what appears to be the right direction: This 3-part call can be heard at slight variation on this Youtube video here of... AN 'I'IWI! Very exciting!

Would love to get some confirmation bias from you all so I'm not just convincing myself of things.

https://www.youtube.com/watch?v=IsZBsOXlR3w