Pokémon Café Mix has put out further details on Pokémon Café ReMix’s update. This update will be released on October 28, 2021 and will feature a variety of changes. There are four new modes for the game:

Pokémon Visit Mode which makes you cook dishes based on customer visits.
Menu development mode, a puzzle that lets you devise a new menu to attract Pokémon.
Training Mode, a mode that lets you raise the level of individual Pokémon.
Extra Order Mode, the mode using the old orders up to 1200. You will get various rewards based on your progress.
Various rewards will be granted to players upon reaching certain milestones for orders:

Order 100 gives you Charmander
Order 600 gives you Pikachu: Chef Costume.
Order 1200 gives you the Lucario Chef costume.
Other mechanics of note:

Stages will have three different difficulties.
Megaphones can now be combined into up to 4 for more effect.
Stamina is to be altered so that it is always reduced by 1, regardless of if you succeed or fail the order. Recovery time is now 15 minutes per stamina piece. Additionally, a new item is introduced that lets you play without the use of Stamina for a while. You can also share Stamina and gain it from Team Members
New Pokémon are to be added including Charizard and various costumes will be made available, based on feedback. Mew will be added to the game with the reopening.