Can anyone tell me where I can buy or have made some '' Disney '' costumes , like Mickey Mouse, Ber Bear, etc. Must be the type that cover the head, not just ears and mask.

Try Pratunam, the building that is part of the Indra Regent Hotel, entrance on the far left side as you face the hotel, one of the shops on the right just as as you enter.

Edit: don't konw if they have specifically what you want but they have lots of costumes and could maybe get what you want. Try taking a picture along.