Field Goal Question

I was playing Madden (09 as I keep forgetting to pick up a newer version when I'm back in the UK) recently and got my opponents on 4th down at my 40 something. Anticipating a punt I selected a punt return formation, but instead he went for a field goal. The kick dropped short and was fielded in the end zone by my punt returner who made it back to the half-way line.

I've watched a fair bit of football but have never seen anythig like this in a real game. So

1) Is it a legal formation for a FG attempt to have a player back deep?
2) Is this normally/ever done?
3) I guess not, because a missed fieldgoal would hand possession over to the opposition at the place the FG was kicked from, which is likely to be more advantageous than any return?
4) If the returner managed to get back beyond this point would that return be allowed? If it went for a touchdown would it count?

It has happened https://youtu.be/K5cZh5CJ7zg

Antonio Cromartie did it in Minnesota. 109 yard TD.

The TD counts, the opposing team can return a kick should they desire.

It works since the FG unit is usually all blockers so a quick returner can outsprint them.

Teams generally only try it when defending a particulalry long FG at the end of a half because, by returning a missed field goal, you loose the automatic field position on change of possession which is based on where the kick was taken/struck... thus in field position terms it is generally quite a bad idea to do

You don't see it that often, though I've seen the Cards try it a few times, usually on a long field goal right before half time when time will expire.