Creating New Features/Effects: All users (especially GMs) are encouraged to develop other creation options and methods for use in their own games. All materials should be built with the documented Incarna Game Design elements.
"But, it’s what my character would do!" - These types of character aspects are not an excuse to be disruptive to the point that it constantly endangers the safety of the group or the story continuity. Find creative ways to work through situations and do not manifest them to extreme levels of Behavior for your own amusement and to the detriment of the group.
Groups are encouraged to adopt whatever Features works best for them – perhaps limiting their options of which a individual PC can take without group approval. This reduces overlap, encourages customization, encourages material familiarization, and expressly creates a circumstance which needs group cohesion even outside the game play itself.
Making characters compatible in a group overlaps many of the same considerations of making an individual character without considerations for the group. Any biases and sitrusts a character might have within the setting carry over to the group. A racial hatred cannot be simply ignored by contrivance, it should require a story showing how it was overcome. A group can have defining events as well. These are highly encouraged as opposed to GM contrivance of forcing the GM to make up reasons you are all adventuring together. Many Gms will reward creating these connective stories with items, CP, and even full measures of traits and kills to distribute among the group.