Rulings

• The token copies exactly what is printed on the creature and nothing else (unless that creature is copying something else or is a token; see below). It doesn't copy whether that creature is tapped or untapped, whether it has any counters on it or Auras and/or Equipment attached to it, or any non-copy effects that changed its power, toughness, types, color, and so on.2018-10-05
• If the copied creature has {X} in its mana cost, X is 0.2018-10-05
• If the copied creature is copying something else, the token enters the battlefield as whatever that creature is copying.2018-10-05
• If the copied creature is itself a token, the token created by Quasiduplicate copies the original characteristics of that token as stated by the effect that created it.2018-10-05
• Any enters-the-battlefield abilities of the copied creature will trigger when the token enters the battlefield. Any "As [this creature] enters the battlefield" or "[This creature] enters the battlefield with" abilities of the copied creature will also work.2018-10-05
• You must still follow any timing restrictions and permissions when casting a spell with jump-start, including those based on the card's type. For instance, you can cast a sorcery using jump-start only when you could normally cast a sorcery.2018-10-05
• A spell cast using jump-start will always be exiled afterward, whether it resolves, it's countered, or it leaves the stack in some other way.2018-10-05
• If an effect allows you to pay an alternative cost rather than a spell's mana cost, you may pay that alternative cost when you jump-start a spell. You'll still discard a card as an additional cost to cast it.2018-10-05
• If a card with jump-start is put into your graveyard during your turn, you'll be able to cast it right away if it's legal to do so, before an opponent can take any actions.2018-10-05