No they will not preform as good as the r9 at most they will preform as well as a 270x. I recommend selling first card and with money that was going to be used for second card purchasing a r9 285 or if you can find one cheap a 290
In order to crossfire u need to have two r7 260x, crossfire only works with two same cards. But it is not a good idea to crossfire two entry level cards, its better to get one 270x/280 instead of 2x260x.
No they will not preform as good as the r9 at most they will preform as well as a 270x. I recommend selling first card and with money that was going to be used for second card purchasing a r9 285 or if you can find one cheap a 290