If by rope you mean para-cord then I'd say yes, 20 to 30 feet or so shouldn't take up too much weight/space. In a pinch you can cut a section off and remove the 7 inner strands for sewing, fishing, lashing etc...
Very versatile for what it is. If by rope you mean actual climbing/rapelling that's a whole other ball of wax, one I am not qualified to give advice on.
One the signal mirror front you can probably find a travelers mirror in a camping section or grooming section that might be small/handy enough to use.

-Bill Liptak