1. Seelah encounters Khorramzadeh, and Kyra is also at her location. They both fail Khorramzadeh's BYA check and are forced to move. What happens?
2. Feiya and Ranzak are at Sharkskin Reef at the start of Ranzak's turn. When Ranzak encounters his shark, Feiya plays dimension leap in order to move to a different location. What happens to Feiya's shark?
The monster remains at its original location but the encounter continues onwards (just at a long range).
For #1, defeating him will still close the original location. Note that this closing only works for villains or other henchman that automatically close locations; you can never attempt to close a location you are not at.
For #2, Feiya no longer gets a shark because she is no longer at that location at the start of the turn. You resolve those in order of your choosing so you chose Ranzak first, and by the time it gets around to Feiya she's no longer there, so no shark for her.