Their friends' reactions would depend on their personalities. Jazz, being the more mature and understanding one, would likely offer her wisdom and support. She might help Sam with any medical or emotional concerns. Tucker, on the other hand, might initially be more focused on how this will change their adventures. But as time goes on, he would come around and be there for them. Some of their more peripheral friends might spread rumors or be distant at first, but as the pregnancy progresses, they could see how committed Danny and Sam are and change their attitude.
Their friends might be really shocked at first. Tucker, for example, might not know how to handle the situation. He could be worried about how it will affect their group dynamic. Jazz might be more understanding and try to offer support, but also be a bit concerned about the practicalities of them being so young. Some of their other friends might be judgmental, thinking they're too young and not ready for this big step.
Well, their friends' reactions could be quite diverse. Some friends might be excited and immediately start thinking about baby showers and helping out. Others could be more hesitant and worried. For instance, if they have some friends who are more into the 'normal' side of life, they might see this as a huge disruption. But friends like Tucker, who has been through a lot with Danny and Sam, would probably end up being very supportive once they get over the initial shock.