I dont think you do, you can get them something really small if you want, like a starbucks gift card or something but nothing major...
Also for the others they are excited about the baby and want to celebrate with their friends and I dont think there is anything wrong with that, its not like your begging for a gift, if someone wants to give one fine, if not fine, so they cant have their family host it...I am doing most of the stuff for mine even though its hosted by my sister in law and paid for by my parents! My sis in law is busy with a kid and my parents are like just pick what you want...