Your Tama will remove the Costume as soon as it goes to sleep!
You just have to wait throughout the whole day I guess.....or.....
TIP:
You can just set the time to your pets normal bedtime and then quickly set it back once it went to sleep!
It should take the costume off if you couldnt stand it any more!
As for what type your Tama is, in case you are wondering you could check the V3 chart if it is a V3, and if it is a V2 tell me if you want me to post one here as well!