The way i see it is if you didnt invite them over then you shouldnt have to run around after them, you are about to have a baby dont these people realise that, its stressful enough when its just you and your partner there with you worrying if you are prepared for the arrival of your bub. I think its bad manners for all the people to come stay with you, you really need all the rest you can get until bubs is here. You really need to sit DP and explain it to him and make him listen, as for his friend i would be telling him to make his own dinner or go elsewhere.

ETA- I agree totally with Maz turn into a crazy pregnant lady and if they dont like it they can stay somewhere else!!