Yes to all of the above. Also try the local council to see if there are any ponds in parks or public spaces that might be suitable for goldfish. Well done for bothering to do something about it and not just flushing them some people would.
We inherited some large goldfish in a small pond when we bought our house. We have never wanted them but have always fed them. I have always felt bad about them, it can't be good in there. Recently 2 died and now I really want to get the others out. After the experience of fishing the dead ones out, I'm having cold sweats over the survivors. The RSPCA say it's the pet owners' responsibility to rehome unwanted pets but I don't know where they can go. No one wants them. Any advice appreciated.