Answer to Question 1
The nature of copolymerization would cause more randomness to occur along the molecular chain than would the corresponding homopolymers. Therefore, crystallinity would be lower.
Answer to Question 2
Bimodal distributions have two peak areas in the MWD plot. These two peaks indicate that some lower molecular weight material has been mixed with some higher molecular weight material. This mixing is often done to improve the processability of a material with a high, narrow MWD. The lower molecular weight material will melt at lower temperatures and provide lubrication for the higher molecular weight polymers, thus increasing the ease with which they can be processed.