Mystery baby fish

Hi all-
I have a few questions about babies. All of my fish, cept two were small
when I got them (this season), including tiny feeders. So I was surprised
when earlier this summer I started seeing babies. I have about 15 of
various sizes. The 'two' were some chunky Shubunkins that were 5-6 inches.
Most of the babies just look like regular comets, although even some of them
are short finned and some long. There are 3 or 4 that look like they could
be Shubunkins. Though they are still primarily gold they do have some black
patches/patterns beginning to form- not the black along the top fin stressed
markings. 1) So my first question is how old do goldfish have to be to
reproduce? Just remembered I also have a sarasa who just has a red band
near his tail. It was maybe four inches when I got it. 2)Now I also have a
baby about the size I got the first one with almost exactly the same
markings?
3)Lastly I have what appears to be an emerging shubunkin (gold with black
markings) but the bottom part of the V of its tail is split. This almost
appears to be a fan tail, except that it is slender like a comet and as best
I can tell the top part of its tail fin is not split but the bottom is.
It is all very curious to me. To have basically immature fish but around
5 different varieties of babies out of only 15 or so.
Being in Austin, the winters are quite mild. For instance, my water temp
is still between 55 and 60, though I am sure it will get colder. What is
their chance of survival. Most of them are only about 2-2 1/2 inches,
although several are much more substantial both in length and girth. 4)If
necessary I am tempted to find a large 'tub' and put a few of the
interesting small ones in the garage or even a 20 gal aquarium with a small
filter, airstone etc.

So - where do you think they came from and what is their chance of survival?
Thanxx
Bill Brister -Austin, Texas