Is it possible to extract slider to another WP theme?

Hello, I don't know PHP as much as I would like to. I'm preparing a wordpress site, which is gonna be a composite blog website. There are two themes that are close to be perfect for me - the Catch Kathmandu and the Newschannel. I'd love to merge them together, using converted slider from CK in the Newschannel. And my problem is, I'm stuck on the very beginning. Could you please tell me from the start if such an operation is first of all legal? I am not sure, if I can do whatever I want with the free themes. If it is possible to combine these two themes, I would be happy to hear from you how to do it ;) My wish is to have the Newschannel theme with a slider from the Catch Kathmandu theme just after the menu. Regards Kicia