Wave 3 DLC will include content along the way such as a new playable character Jeritza, who has appeared in Garreg Mach but only for a few quests. There will also possibly be support conversations with him in them. New online features and activities will be available, as well.
For paid DLC in the third wave, Anna will become playable once again. There will even be a paralogue that involves Jeritza and Anna. Then there’s new quests, activities, costumes, and battalions. This is more content compared to the first two DLC waves.
The last DLC wave currently has no signs of free DLC. However, it will include a new side story that has been hinted at since the first DLC’s reveal. New playable characters include Juris, Balthazar, Constanze, and Javi, according to translation. There will also be more support conversations, monastery facilities, hero relics, new costumes for both Byleths and Sothis, and so much more.
This is a lot to take in considering the amount of content Three Houses will have overall. The 16th Fire Emblem entry will undoubtedly provide many hours of content and be a perfect contender for Game of the Year.