Hi noob1! Welcome to the forums!
1)if the person i send it to denys it will i still get my irc`s back?
If they send a letter saying they don't send autographs, you may get them back, but if they never respond at all, you probably won't.
2)while reading the instructions it said if i dont live in canada to put 7 irc can i put less since i live in canada there $3.50 each!! (I'm not good with IRC's

, but I agree with starreyes

!)
3)has anyone tryed getting shawnee smith`s autograph (from becker and saw)?
Even though there have been no successes yet, I would still send a request with a SASE and maybe a photo for her to sign. I have received (and have seen many people receive) autographs from stars who have no feedback reported until someone posts the first one.
4)do i need to include a pic for them to sign or do they give me one with the autograph?
I usually send photos, but celebs will usually sign a headshot for you. If you are looking for a particualr picture for them to sign, I usually do google image and search for large or wallpaper sized photos.
5)can i email them telling them if they can send me an autograph by mail?
Some celebrites send autographs if you email them, but be ESPECIALLY cautious while sending emails (I usually make sure the celeb has responded to others before I email them) because with the internet, you never know who gets or reads your emails, so it may be unsafe to send your address if you aren't sure if it's really the celebs' email (the ones in the database are safe

, I usually stick with those. )
Hope I helped!