Mr_Morningstar

Main preview - https://youtu.be/0nnshmUork8

Oct 13 onwards on Netflix

yes

It has now

Most probably on Netflix

This series received a 15 billion won investment from MBC and Wavve for its production. It is labelled as "MBC's 60th anniversary special project"(Wikipedia).

Episode 1 is available on iQiyi - https://www.iq.com/play/1sc92a3v8bh?frmrp=explore_library_2&frmb=filter_result&frmrs=0

New teaser - https://youtu.be/B4n5wgT-Y_0

New teaser -https://youtu.be/KoeAG4NYs28

New teaser - https://www.instagram.com/tv/CTDwph5DnO4/?utm_source=ig_web_copy_link

All episodes are available now on Netflix - https://www.netflix.com/title/81280917

Here - https://youtu.be/huTOivFBXFY

Nope

New teaser - https://youtu.be/O8PlKIC3B9A

"The actors of “Hospital Playlist” will be starring in their own variety show!"
https://www.soompi.com/article/1485301wpp/hospital-playlist-actors-to-star-in-new-variety-show-by-pd-na-young-suk

"It was through Netflix that Hwang Dong Hyuk (Director) was finally able to bring his idea to life after 10 years of planning. “It’s a challenging project, so I was able to have physical and psychological freedom [through Netflix],” he said. This is the first time that the director has taken on a series rather than a movie, and was able to exercise more freedom about the story’s length, content, and worldbuilding."

https://www.soompi.com/article/1485185wpp/lee-jung-jae-and-park-hae-soos-squid-game-unveils-main-poster-director-reveals-story-took-10-years-to-plan

First teaser - https://youtu.be/7fM5it4SFnA

Nope not for now but may be added later after airing.
You can request here - https://help.netflix.com/en/titlerequest

New teaser - https://youtu.be/q1dQy-YQuHg

New teasers - 1) https://youtu.be/p69_qmggwpQ
2) https://youtu.be/hrDZF2wMVyk