RTF is a global modification that replaces all towns in the game.

I doubt that Sarah and Kirill are dead. Zana could very well be serving Kha-Beleth at Kirill's request, as Kirill sent her to the Lord as his agent. (According to the lore, neither Railag nor Kha-Beleth knows that Kirill has been resurrected and is still alive – from this, we can assume that he and Sarah are acting secretly.) Zana didn't make things easy at the end of Dark Messiah; she asked Sareth not to release Kha-Beleth – perhaps that's why she ended up where she did. Kirill needed to control the situation somehow and put obstacles in the Lord's path.
Jorgen will most likely appear as an advisor to the human government (which is where he usually appears).

Added 9 minutes later
By the way, here's an interesting idea: since Lina is dead in your version, based on the prophecy of the human race, the end may come for them. Here, you can play with the return of Kirill and Sarah as leaders for those whom the surviving humans will follow, and so on. After all, the death of the Falcon dynasty should lead to the decline of the human race, and they themselves are unlikely to die – that is, Kha-Beleth must oppose the humans and defeat them, which will lead to the death of the Unicorn-Deer Chita – that is, the human race is beheaded, and the remnants of humans are already uniting with the remnants of elves, dwarves, etc., as you plan