Your Sims will not be saved to your library or the gallery with your build. In other words, people downloading your lot would not get your family.
There are 3 ways to move a Sim out of a lot. In game play mode click your phone and the car icon, then "move household". I map mode, click the house,a blue arrow will appear in the right hand corner. To the left are three dots, click dots (more) and click the truck. Or you can also move them out by going into manage households. The icon looks like 2 figures and a pen. Manage household you can find under the three dots or at the very top of your screen to the right. ( in map mode ) I hope that helps