Your houses turn purple and all the roofs disapere and you can't reverse it.
They get taken away
I don't think you can
did you delete the mailbox? if you delete the mailbox on that particular lot, none of the sims will be able to interact with the visitors. as far as i know, if you've already deleted the mailbox, that lot is pretty much screwed. move your family out of that lot and into a new one and this time just deal with the bills. but this is only if you're playing the first sims; i couldn't tell you why if it the second or third sims.
Don't think you can, sorry.
it should be in the front of the house next to the trashcan.
That happens in sims 1 and in sims 3 for iPod touch Mabel other sims too
You cant, buy a computer
you can only open a mailbox if there is something in it. however, if there is then I can't help you with that
Cast away its way better
You cannot make a sim nude in Sims Castaway.
You shift + click the mailbox and spawn should appear
Your sims will become mermaids/mermen