So I entered the lot of Carla Devivio Sunday night and their toddler, Gibson was invisible and could not interact/be interacted with. He was still selectable and his needs still dropped. I tried everything I could think of (batbox, teleporter shrub, moving the family out and back in, installed a week-old backup) and nothing worked. Last night I did a system restore and re-installed the backup from last week. He was still missing. I then installed a back-up from the end of round 7 and the toddler is there... but that means I'm going to have to start Round 8 all over again. I'm guessing the character file got corrupted sometime since I started Round 8, every other lot seems to be working fine. I'm going to try some other stuff tonight and see if it works. If I can isolate his character file I can probably pop it into my more recent back-up and hopefully it works ::crosses fingers:: Hopefully my game isn't imploding... Wish me luck!
Update: I replaced Gibson's character file with the un-corrupted one in my June backup (the last time I played the lot) and it worked! Plus I didn't lose any lots that I played for Round 8 -- YAY!! I don't think my game is going screwy but it definitely worried me!