The collection of documents seems to be guidelines and templates to begin from if seeking to partner with Netflix.
It doesn't seem like requirements for the film from being considered for inclusion in the catalogue, but at least offers a relative standard that can be deviated from as necessary.
For example, the general safety and guidelines document they provide for the US includes guidelines on weapons handling and stunts.[1] Having documents like this to start from might remove some of the administrative overhead to creating art in film.
To offer a comparison, YC has the SAFE investment template, an enterprise sales agreement template and recommendations for organization of startups. Using these might make a new company an easier fold into the portfolio but if the startup is successful enough, many things likely can be seen past.
Regarding iPhone specifically, the device has been able to record in 4k since the 6S and 6S Plus, which was one generation later than Tangerine which used the 5S. That said, I don't know the details of video capture to say if anything up through the 13 Pro compares with these other cameras.
[1] https://drive.google.com/file/d/1gs6n32bMC_2zLGp2jI4U3JA7k7q...
To clarify, I believe this is for original Netflix content (partners) where Netflix does the production. 3rd party studios licensing their content would be exempt from this (ABC/NBC/CBS/FOX). The big issue is that you have to get pre-approval for non-approved cameras.
I suspect that Netflix/Apple/Amazon is trying to make their name in content beating out cable and movie production studios. High quality 4k video is what people are clamoring for. I've seen a lot of cable/broadcast 1080p (The local CW station comes to mind) that's been recompressed to a lower bit rate. Effectively giving you 720p resolution in 1080p format -- it's not nearly as enjoyable.
Pretty sure some of their other original stuff was shot on film too, which obviously wouldn't meet these requirements. At least, I know the non de-aged scenes for The Irishman were done on film. But again, maybe the big guys get more leeway here.
Any company that produces something will have similar type of "specs".