The additional 1 damage from Far Fortune’s last ability is dealt by the same source as the original source of damage. The damage isn’t dealt by Far Fortune unless Far Fortune is the original source of damage.

If another effect modifies how much damage your sources would deal, including preventing some of it, the player being dealt damage or the controller of the permanent being dealt damage chooses an order in which to apply those effects. If all of the damage is prevented, Far Fortune’s last ability no longer applies.

If damage dealt by a source you control is being divided or assigned among multiple permanents an opponent controls or among an opponent and one or more permanents they control, divide the original amount before adding 1. For example, if you attack with a 5/5 creature with trample and your opponent blocks with a 2/2 creature, you can assign 2 damage to the blocker and 3 damage to the defending player. These amounts are then modified to 3 and 4, respectively.

“Max speed — [ability]” means “As long as you have max speed, this object has [ability].” If the granted ability functions in a zone other than the battlefield, the max speed ability does too.

A player “has max speed” if their speed is 4.

Each player tracks their speed (or lack thereof) separately. Increasing your speed has no effect on whether another player has speed.

Your speed doesn’t change until a spell or ability says so, such as the inherent triggered ability that cares about opponents losing life during your turn. Notably, losing control of permanents with start your engines! doesn’t affect your speed.

If an effect needs to know what a player’s speed is and that player doesn’t have a speed, their speed is considered 0.

Start your engines! isn’t a triggered ability. Increasing your speed to 1 is something that happens as a state-based action as soon as you control a permanent with the ability. Notably, this includes gaining control of a permanent with the ability that another player controls.