commanders need to be drafted normally in the draft
Changes to Color Identity:
Hybrid Mana counts as either / or as long as it is in the deck
Any multi-card can be player in a deck if at least one card half can be played (Split Cards, Afternath Cards, MDFC Cards,...)
Partners
specific one-color commanders are partners, even if the card does not say so. Online they have the tag "Partner", offline the sleeve will me marked with a red dot