Starlight shop explanation

Hello,

Please help me understand how rotations in starlight shop work...

- Starlight festival tab : does everything change ? every 3 months ?

- Starlight return tab : Are all game skins available in the "Starlight skin chest" worth 2300 ? Do the tab items having no timer limit stay for good ?

- Rewards tab : permanent ??

Thanks in advance and have a great day !