Do the games I got from Xbox Game Pass remain playable if I cancel my Game Pass...

No. In order to continue playing the games, you either need to renew game pass or purchase the games.

All answers in this thread are correct. Also, please do bear in mind that (most) Game Pass games will be available for a long time span, but they will leave the service after a while. If you really love a game, it might be a good idea to buy it while it
is on Game Pass. You'll get a 10% to 20% discount on the base game and a 10% discount on DLC.

If you'd like to read up on this and more, please check out
the FAQ.

On a slight tangent, but definitely interesting to know.
Xbox Wire provides insight in games entering and leaving the service.

If you found my reply helpful, I'd appreciate it if you'd upvote it. If my reply provided a full answer, I'd appreciate it if you'd mark it as such.

Unfortunately, Once your game pass expires or if you unsubcribe the games you have will not be payable anymore. You will lose access to all games under game pass.

If you cancel your subscription to Game Pass, Unfortunately, the games will no longer be playable for free. You would need to purchase from online xbox store or your local store. Or you can continue the subscription service and keep playing!

No. Same as with Games with Gold, you need to have a current Xbox Game Pass subscription (or Xbox Live Gold subscription) to play games downloaded associated with those programs.