I would personaly would like to fight the flood in firefight and im surprized that no one has even brought up the topic so im intrested on what your guy’s opinion on this topic.
About everyone. If you havent noticed people all over the forums have been asking for this 
Would be awesome, but doesn’t seem like that would be possible; I’m no expert, but they would have to be coding new behaviour and creating models and all the other components that goes into creating enemies, and I don’t think that much stuff can be added via dlc.