1a) My first was done for breech. My membranes hadn't ruptured yet, and there was no issue except that he was upside down. While there may have been issues if labour had continued, there weren't any issues at the time. (I personally feel that the staff panicked when they realized they had a "missed" breech on their hands. It wasn't "missed" - he turned after labour started.)
1b) My second was also done for breech. For a lot of complicated emotional reasons, I panicked and caved in when my doctors wouldn't listen to me. She was found to be breech at 39w, 3d (surgery was two days later), because "the baby is too big, and it's not possible for her to turn before labour". Not necessary. As I say, maybe it would have been once labour started (and subsequent births with dh as the father suggest it would have probably been at least another week). In any case, it wasn't necessary, and it was my only labour-free section, and it sucked in every respect, including dd1 being my only baby with jaundice and my milk being quite delayed.
1c) Post-dates. He was fine. There was no issue whatsoever, except that I'd had two prior sections, and he was "overdue" (as was dh, as were all three of his siblings - seems that post-dates and big babies are in his genes). That's it. OB threatened to drop me at 41w, 4d, if I didn't cave and have the surgery, and for some reason, I actually thought that would be loss of some kind. (DS2 was obviously suffering greatly from his extended stay in my toxic uterus, as his initial apgar was only a 9.)
1d) This was my stillborn son. Obviously, things had gone wrong, so I guess the c/s was "necessary". But, he was engaged in the birth canal - since he didn't live, anyway, I'd have much preferred to grieve without the hideous surgical recovery on top of it.
1e) There's no question this one wasn't necessary. DH wasn't willing to have another bab if I didn't have a c/s, and I certainly wasn't up to dealing with it if the cops and/or CPS showed up again if I tried to homebirth. So, I just caved, and climbed on the stupid table. The only indication for a section was that I'd already had a bunch.
2) It's complicated, and there are many factors, physical and psychological. However, I believe that if my uterus hadn't been hacked up three times previously, and if I didn't have nerve damage in my pelvis from the third one, Aaron would have survived. I've also come across some things that indicate that both miscarriage and stillbirth are increased in women who have had c-sections. But I've got about 6 years of research on these issues under my belt, and rarely bookmark anything, so I can't give you any more details than that. (I tend to weigh what I find, make my decisions, and then forget the details of how I got there.) The psychological aspects are more complicated, and I don't like talking about them, because I know I blew it...but without my previous experiences, I might have been slightly more willing to transfer to the hospital for medical "care".
This is all purely speculative, of course. I don't even know what actually killed him. It's possible he had something wrong, and if he'd survived the birth (either a successful VBA3C or a scheduled c/s), he would have died, anyway. I have no idea. (They don't release the autopsy results to "unqualified" people, and I haven't yet reached the point where I can stomach talking about Aaron with a doctor.)
I hate that I ever had a c-section, let alone five. My entire "birth" history has completely broken me, and I have pretty serious doubts that I'll ever be fully emotionally functional again.
FWIW, I was also "born" by scheduled c-section (after my mom's midsection was butchered getting my brother out) and I hate that, too. It's creepy.