For friends, they need to do an age estimation only.
To publish globally for <16 users, the id check and subscription requirements then apply.
In the linked page, point 2 literally says this:
Publish to 16+ and Trusted Friends - To publish a game that reaches Trusted Friends and users over 16 you must:
a. Complete an age check b. Have an account in good standing c. Have an account on Roblox that’s been on the platform for at least 2 days
In the linked page, point 2 literally says this:
Publish to 16+ and Trusted Friends - To publish a game that reaches Trusted Friends and users over 16 you must:
a. Complete an age check b. Have an account in good standing c. Have an account on Roblox that’s been on the platform for at least 2 days