1) You use your pouch for as long as you're comfortable doing so, ie as long as you can without getting skin irritation or leaks. Everyone is different in that some get longer wear times and some get shorter wear times.
2) If you're not comfortable telling people you've had ostomy surgery, just tell them you've had tummy problems and had surgery to correct it. Most people are happy to leave it at that. I usually give them all the details though and have never had a negative reaction to it. The bottom line (pardon the pun) is just tell them what you are comfortable with telling them.
3) I can't help you with this one since I'm an Aussie but I know others will be along soon and will be able to help you out with this one.
Good luck and welcome to the board :)
I have had an ileostomy for 30 years now due to UC.
I'm not a complete idiot - some parts of me are missing!