No Amjoie - eps do not break your added lots in former worlds - not EA's or any of the User created ones I have successfully added lots to. I have a lot of longevity saves from both original Sunset Valley (26 generations) and Caw worlds Mesa Valley II and Longview II - and even with the borage of the WE - it has in no way affected already finished saves. So the save is worth keeping safe for all future use once you get it the way you are happy with it. Once I get a good save - I may make at least 2 copies of it, leaving one on my desktop sims folder and a copy of it on my backup harddrive sims folder. I have everything backed up at least twice and update as needed - but i always keep a copy of the original save with all the changes and so far not one save has failed me yet or broken.
Elanor - unfortunately there is no way to predict where either of those will spawn -but once you do see them spawn in one place in a new game start you will see more of the same spawn in that same place - that's why I mentioned before to just keep a look out for them. Unfortunately they will also spawn in other places too, but they generally always have repeat spawnings where they have spawned before.
Another thing you want to be on the look out for in a new world is if you send your sims on WA, where on the map they leave your town and then where they return. Make sure that area of return is not a trap spot or your own sims might get trapped.
