I see two separate questions/ things in this thread/ OP. The first thing is to be able to modify string1/2, but as stated by others you can just create a string and save it in one of the 100 skills.
The second thing is that you want to attach 2 actions to your entities because of editor/ ingame differences. Alternatively, I think it would be a better way to save additional data in a *.txt file from which you then load map editor related actions for each entity if necessary (and suppress the execution of the actual entity action).