Stealing other peoples clothes is fine as long as you chat to them ooc about it! Any consequences of that will come from the characters she is robbing off, I am sure! She is also able to remove the watch, though let me know if she is removing it whilst not on the train! On the train it is fine not to wear it. Colouring it should be possible depending on how she plans to do it.

Opening a window won't be possible. There aren't any catches or hinges or ways to open the windows. She can try and break it but will find that no matter how strong she is, how much she throws at it and whatever she tries they cannot be broken. Have fun trying Yuffie!

I am very happy to hear about her shenanigans, that's what this page is for!