Go to the Main Menu, and right by the big play button is the Create New Household button. Click that and create who you need. Hell, create one big Ex family. Then just leave them in the tray and not move them into anywhere. You don't click the checkmark which is 'Play' but the folder at the top right which is 'Save Household'. Households listed as 'Not Currently in World' still show up in the game, they just don't have any place to live.
To edit already in game townies, go to your options menu from in game, then click on 'Manage Worlds'. From there, there is an icon called 'Household Management' where you can see all the households 'Not Currently in World'. You can't edit genetics, but you can change clothes, hair, delete, and add Sims.
For size changes, I THINK its Ctrl+] when you're holding an object. Be careful, as I don't think it has an upper limits.
OH, for the thread: When moving a window, art piece, what have you on the wall, hold down ALT for precise, non grid placement. It doesn't work on x-axis or y-axis sadly (horizontals on walls), but does work on z-axis (height).