What happens to spells with persistent effects when the caster of the spell leaves a multiplayer game?

Question

Scenario

There are 3 players in an EDH match, players A, B, and C. Player A casts Modify Memory, targeting creatures controlled by B and C and it resolves, so B and C control creatures from the other player. On the next turn, B attacks and kills A.

Question

Does the effect of Modify Memory persist now that A (the caster of the spell) has left the game?

My Interpretation

After reading the rules, I believe that the effect does persist. The rules state that when a player leaves the game, anything controlled by that player is either returned its owner or ceases to exist. Since player A doesn't control either of the swapped creatures, there's nothing for them to return to its owner. Also, since Modify Memory has already resolved, there's no spell on the stack to remove from the game. Finally, since it's not a permanent it doesn't behave like an enchantment where its effect is removed once the controlling player leaves the game.

Appendix

Modify Memory card text:

Sorcery

Exchange control of two target creatures controlled by different players. If you control neither creature, draw three cards.

Rule for when a player leaves the game:

800.4a When a player leaves the game, all objects (see rule 109) owned by that player leave the game and any effects which give that player control of any objects or players end. Then, if that player controlled any objects on the stack not represented by cards, those objects cease to exist. Then, if there are any objects still controlled by that player, those objects are exiled. This is not a state-based action. It happens as soon as the player leaves the game. If the player who left the game had priority at the time they left, priority passes to the next player in turn order who’s still in the game.

Answer 1

The creatures stay with their new controllers after player A leaves the game.

Modify Memory's effect is specifically a continuous effect created by the resolution of a spell. That is not any of the things that are listed as affected by a player leaving the game, so it persists after player A leaves the game.

A few of the rules in section 611 support this:

611.1. A continuous effect modifies characteristics of objects, modifies control of objects, or affects players or the rules of the game, for a fixed or indefinite period.

611.2. A continuous effect may be generated by the resolution of a spell or ability.

• 611.2a A continuous effect generated by the resolution of a spell or ability lasts as long as stated by the spell or ability creating it (such as “until end of turn”). If no duration is stated, it lasts until the end of the game.