RAI, with the Echo Knight, is it supposed to be susceptible to Fireball? How about Shatter?

Invoke Duplicity: Does it take your spell concentration slot?

If you have Acrobatics can you use Dexterity for jumping distance?

Can a creature use its Multiattack even if one or more of the attacks can’t occur?

Observant Feat says +5 to passive Perception and passive Investigation. What is passive Investigation?

Why does crossbow expert specify that the bonus action requires a ‘loaded’ crossbow?

ERRATA Crossbow Expert (p. 165). The word “loaded” has been cut from the third benefit.