Missing Bodies

First of all, have you downloaded any custom naked skins for your Sims? It may be they don't show up or may not be compatible with certain expansions (due to needing updates or made within one game, etc). Although, I've only heard of mods or hacks doing this.

Have you tried deleting the Sims and then returning to the lot? Sometimes it just reboots the Sim. Not sure if it will work, but it might, pending on the type of problem you have. If you don't know the steps for this and you would like to try, you can check back with the post above. I need a recap on how to do that as well, anyway.

I'm not sure if this is the best advice to give, but you could try to download new naked skins.

Also, just a question ~ did you happen to just download these expansions all at once? Or did you test the game in between each download to see if they were working correctly (sometimes it helps going in and playing with it for awhile to make sure). I just ask because I downloaded two in a row and all I did was go into the game and check out the neighborhood. Little did I realize my game was messed up until I actually went into some lots and found out that the families had been corrupted. This option, however, may not be the best tip. Re-installing should always be your last resort.