I have some questions and would like to vent my story as well.
(I will try make this as short as possible)

(the back story)
After 12 years of having a pond, and going through roughly, 150 poor Innocent goldies, (commons/comets)  this is where I'm at.
4 years ago I decided to stalk my pond up. (hoping to get them breeding) Loosing several fish over the years, do to pond liner tears, racoons, bears, you name it, I was down to 13 at the beginning of this year (still hoping they would breed)
Like every other year I take them from my indoor aquariums and transfer them to the pond as early as possible.
(usually april or may)
They were pretty small about 3-4 inches or so, roughly 4 years old. (bought them when they were babies) But once they hit that pond this year, they started growing at an accelerated rate, and shot up to 4-6 inches. Little did I know that they were breeding.

(the now)
Last weekend, I decided to pull them out of the pond early, (usually I wait till it freezes over, being busy, etc)
and I see a small goldie! (was so excited)
So I get the coolers ready, fill em up with water, (separate cooler for the babies) and I start fishing with the net.
I managed to get almost all the babies out the first night, and a couple of males, and 1 female. that was very noticeable to my untrained eye.
I made sure to close the lids on the cooler, ("w/e can go wrong, will go wrong" apply's to me) before I  went to bed that night. I wake up in the morning and I wait for sun to bring the goldfish about in the pond, and I go fishing again.

I managed to get all the babies out and a total of 4 adults, 1 mature female and a couple males. Luckily I stopped for the day, (I forgot to close the cooler lids the 2nd night!)
I wake up in the morning and see that they're all gone, except 1 baby fry. (just furious at this point, and kicking myself)

So right now I'm left with 4 adults. (still waiting to get 1 more from the pond, that I couldn't get)
The chances of the 5 fish I have left breeding, is looking slim. and I really would like to get them breeding again next year.

(Questions)
-Considering 1 male still has breeding markings, what could I look for in the others, to determine there gender right now?
-Also, when do you think the fry hatched if I put them in the pond in may?
-I counted 15 babies in total, how many could one female breed her first year?

I heard somewhere that you can put screening over your pond (like the stuff for screen doors) to discourage predators.  I also have seen metal pond covers, but your pond may be too big for one.  I'd try a decorative wood or stone bridge they could hide under.
If you can't tell which ones are females, don't be disappointed- I can't tell which are rounder or have a protruding vent.