The explosions are just visual effects and have nothing to see on whether or not she survives. I haven't look at the scripts because I don't have the game with me but i assume there should be a script to make her die. So even if you remove the explosion effects, it won't change anything. You'll certainly need to replace some scripts located in Trask's dialog and in the utc files of the two jedis (spawn script and user define script) and redo the dialog. I could be wrong about the functions since I haven't checked the files.
As for the portrait, just take a screenshot of her during the game, save it as a tga file and add a line to the portrait.2da file that will be referred to in the utc file. For the format, see this thread:
http://lucasforums.com/showthread.php?s=&threadid=128548)
For the rest, DarthTomer directed you at the tutorial thread, which contains the recruitment script. I suggest you download one of the recruitable mods and compare the files with the originals that are in the game.