1.No, sorry... you can't. You can in the nintendo version, but not in the PS2 vesion. Sorry.
2. How long? Depends on how much you work for Bob. Also, give him cakes after you get the kitchen added on to your house. He likes cake. Then, if you have a good enough relationship w/him, he'll bring the horse that likes you the most up to your house, and ask you if you want it. I would save after every day, and then if it isn't the horse you want, say no, and then don't save after that day, and see if he does bring up another horse the next day. If still isn't the horse you want, then repeat this process. I got the horse I wanted on the first day, so I don't know that if you say no, he'll bring another one later. He probably will, but I don't know.
3. You get the flute from Louis (the tool shop guy). Get up a good relationship w/him, and eventually, you'll find him by the fishing lake (or is it at your house? Maybe by the tool shop? I forget...) and he'll give it to you.