@SheriGR There is a mod that I now consider one of those must-have for those who play with mods. What it does is that it will take any homeless sim in your game and force the game to use those sims instead of creating new sims. It has really cut down the number of those awful sims that the game will create just to fill in a slot, and it will force the game to use the same sims instead of creating new ones. If the game is short it will still create a new sim to fill in the slot needed. But what I will do is to make sure I have my own and make sure you have a few sims of each age group as homeless, and this mod will force your game to use them.
http://www.modthesims.info/download.php?t=604590