Yes, it is possible to have complete control over rival respawns. Before 0 AD, you can force the AI to respawn where you wish, and move that spot wherever you like, by turning "on and off" each area's eligibility to host a respawn, by building or disbanding your cities. Or, more elegant, herd a rival empire to an area, let them found cities where you force them to, and let those cities then block off the area to respawns. Whenever possible, put your rivals to work for you.
After 0 AD, you lose such fine neighborhood-by-neighborhood control over respawns. But until 1750 AD you can still control which landmass your rivals reappear on, by manipulating which landmasses contain cities. Look up a thread here called "Checkmate" from May of 2016, there's a picture of this exact situation.
In a natural game, the AI chooses a spot where it would do a respawn, if one is called for during your turn. Not always the exact square, but a potential respawn square, and the actual respawn occurs on an eligible square within one square of that pre-chosen spot. The AI moves that spot around every turn, depending on the locations of cities around the world. Thus, with a program of founding, disbanding, and shepherding cities, you can manipulate where the AI places that spot every turn.
No cheats needed. The real key is to knock out a rival's Palace. The Diplomat is truly the most powerful piece on the board. Without a Palace, a rival is no threat to anyone, but themselves. You can force them to pick up their whole empire and move hundreds of miles away onto scrubbier land, even onto an island of your choosing. You can force their Settlers into slavery, developing land which you will own later.
Before 0 AD, you can put them to work for you, anywhere in the world. And because of respawning, you can have up to 12 puppets throughout the game, so no guilt about killing one off when you need to. With no Palace, a rival civ is basically your plaything.
