Hello!
Thank you for all your support! I'm so happy to see you're enjoying the game!~
1. Yes! You can obtain keys to all of the locked rooms. They are hidden very well though, so it would take some searching around through the kingdom!
2. Yes, there will be a way to obtain him in a later update! Unfortuntely I cannot tell when that will be yet since the slaves in the stock will all have to be fully implemented first.
Thank you and have a nice day as well!~