You must still follow any timing restrictions and permissions when casting a spell with jump-start, including those based on the card's type
It runs a full playset of Llanowar Elves, the only four-of in the deck, which gets things going early
Illustrated by Simon Dominic Standard Not Legal Alchemy Not Legal Pioneer Not Legal Historic Not Legal Modern Not Legal Brawl Not Legal Legacy Not Legal Comp
No, only the commander that dies, or is moved out of the battlefield can be put back in the command zone
For example, Sidequest: Play Blitzball buffs a creature each turn and asks you to deal 6 or more damage to a player
The obvious place to start is cards which trigger when they become tapped, or when other creatures become tapped