Tokens, copies, creating, and replacing

Tokens are game objects that are not cards, and copying changes what an object looks like without changing what kind of object it is. Keep those two ideas apart and most rulings fall out.

Worked example. You hold a battlefield and your legend is LeBlanc, Deceiver, so you discard a card and exhaust her to play a ready Reflection token there. It starts as a 0 Might token with no text, then becomes a copy of another unit there, your Honest Broker. The copy effect has its own layer, applied before Trait-Altering effects (rule 479.1 and rule 479.2), and it copies the Broker's copyable traits, its printed traits including Might, cost and rules text (rule 479.1.b.1). So the Reflection now has the Broker's name, 2 Might, a cost of 2 and its Deathknell. But it is still a token: a token can't lose its token nature (rule 185.1.a). That is why it moves to the trash when it dies and then ceases to exist (rule 186.1), and why Temporary will kill it at your next Beginning Phase.

What a token is. Tokens are created by spells and abilities during play (rule 180). They follow the rules of their type, so a token unit has Might, enters exhausted and can be chosen by anything that chooses units (rule 185.2.b and rule 185.2.d). A token's controller is the controller of the effect that created it, and that player is its owner (rule 182 and rule 183). Tokens are domainless and have no cost, so their cost is treated as 0, although layer effects can append a cost or domain (rule 185.3.a.1, rule 185.3.a.2 and rule 185.3.b). Tokens exist only on the board or the chain, and one put into any other zone ceases to exist right after it moves there (rule 186 and rule 186.1). A token inherits the recycle destination of its type, then vanishes (rule 185.2.e).

Creating. Creating produces a game object that did not exist before (rule 440.1). If the effect names no zone, a permanent is created at any board location it can be played to (rule 440.2.b.1). "Play a 1 Might Recruit token" creates the token on the chain, since it is played, while "Create a 1 Might Recruit token" does not name a zone and so creates it at a board location (rule 440.2.c and rule 350.2).

Copying. A copy takes the object's copyable traits, which are its printed traits, or the copied traits if it is already a copy (rule 479.1.b.1). For a token with no copy effect they are the traits it had when it was created. Later layers can change the actual traits without changing the copyable ones (rule 479.1.c).

Replacing. Replacing creates a token in the place of another card or token without playing it, and the token inherits all effects and statuses of what it replaced (rule 439.1). Effects that reference the original treat the token as the same game object (rule 439.1.a). The replaced object goes to Banishment, where it is considered Replaced, not Banished (rule 439.4, rule 439.5 and rule 439.5.a). A replaced token stops existing once it enters Banishment, and the replacement still stands (rule 439.6 and rule 439.6.a). Some tokens can be swapped back: the token stops existing and the original returns to its space with its current effects and statuses (rule 439.7 and rule 439.7.b).

Common mistake. "A copy of a card is a card." A token that copies a card is still a token.