Jon Carter: His friends would be curious for sure but I think they'd get mighty pissed at dear old dad for his treatment of Booster. I could see their reactions going from amazement (that Booster could have this guy as his dad), sympathy, anger and maybe a little satisfaction that the mans' son accidently shot his ear off. Lots of pep talks would have to follow to let Booster know none of his fathers' words were true.
Daniel and Rose: They'd get a kick out of meeting the present day ancestors of Booster. Daniel would be someone they'd tease him about but I think they would find it interesting that they share so much in common. Including the story of the Supernova suit. Rose would surprise most of them (not Bats of course.) Both in regards to her being related to him and how she ends up with Daniel. But I think people over look a quality she shares with Booster that Daniel doesn't: their both ambitious people. During the Johns/Katz run she kept looking for her story even if she admitted she might not be seen as a "real reporter." It wasn't until she realized that she had to keep a lid on it that she actually stopped. This series might be a better fit for her than BG.
Michelle: I honestly don't know if most of them are even aware that he has a sister much less a twin. He didn't mention his scandal to them until Jurgens JLA and he never mentioned her after her "death" until CTIC. If most of them don't know then only Batman and Guy should know this information since they were present for her funeral (neither actually met her.) I know I said it a lot but I want Guy to assume she's a "Gal Gardner" version of Booster. I'd expect everyone else (not Bats of course) to be shocked over this. Then Bea and Tora want to become best friends with her. Bea goes into her "protecting the girl who's new to the world" mode which amuses Tora and ticks Michelle off. If Michelle got mad over Booster trying to shield her from her "death" I don't think she'd put up with Bea babying her.
Rani: She would shock them more than the others. I think they'd be upset that there's so much of Boosters' life they aren't aware of and Rani would cause them to rethink their opinions of Booster. Now I don't see him as her father as he never really accepted the role (no I didn't buy the "belief in god" thing they forced in.) I see this as Michelle as her parent figure and Booster as the cool uncle. Even still Rani would touch them since she suffered through so much and obviously adores Booster. I think she'd freak out when she meets Bea though. Because seeing a powerful woman with green hair would likely bring back bad memories. BTW, isn't Guy trained in kid psychology or something?
Rip: Bruce kinda met him during his "can't explain why I'm kinda leaving you to die" scene in TROBW mini. I think their reaction would differ based on what the situation was--whether they find out the truth of Boosters' mission--who Rip is--etc. Before Gavril came around I thought Bea would hit on Rip, much to his discomfort. Rips' cool but sometimes people (Superman) can't see that because of their own views. I think Rip at least would know them all well enough because I can't imagine him not visiting them growing up. Since finding out who he is I had this image of him causally walking through the chaos of JLI without it phrasing him much.