New program based on 2 differently-licensed previous ones

["Cameron Dale" <camrdale@gmail.com>]

Hi,

I'm creating a new program for Debian (not just packaging, but the
entire program), and I have some questions about the license I can
use. Some parts of the code are based on a previous work released
under the MIT license, while some other small parts are based on GPL
(v2) code from a different work. My questions are these:

1) Can I release the entire program under the GPL?

2) Do I NEED to make reference to the other works? Should I?

3) Can I remove the headers in the files that I have modified that
state the original authors and licenses of the files?

Thanks,
Cameron