Coupla things:
Regarding length of training- that will change with the 6 year programs up and coming. One can do a Peds CT fellowship following the 6 yr program, with elective time focused on Congenital in the 6th year, if one so desires.
Regarding fellowships- there are like 9 ACGME accredited programs now. And more on the way. But as some have correctly stated already, the big problem is where to find that first job. Despite the fellowship possibilities, there are just very very few jobs out there. And even then, you are like a junior attending for some quite time, taking q2 call (or more!). So it is a big gamble.
Regarding reimbursement- for a while as a junior attng you may be making in the 200-300k's, but it should be stated that if you do finally make it to the senior level there is BIG money. There are so few of these people who REALLY know what to do and have that type of experience that they can make >900k-1mil/yr. But it is a loooong way to that payday, for sure.
Regarding hierarchy- hard to say overall, but in the CT world at least they are extremely well respected
Regarding "innate talent required" - I have heard this too, from various people at various levels of training, but never from an established Peds CT attending. My personal belief: if you can get into a CT fellowship, then accepted by a ped CT fellowship, plus have the desire and dedication necessary than I think its definitely doable.
Regarding Pediatric General Surgery - at my school they'll put kids on ECMO and do some PDA closures, but no coarcts or anything else. Also someone posted earlier that you can do a "congenital heart fellowship after a pediatric general fellowship". This is false, only through a CT fellowship or Integrated CT program can you get near a pedi heart.