Depends on the suit with regards to whether you would wear it to a wedding. If it obviously looks like it's a business suit, then don't wear it to a wedding. However, if it's obviously a suit that you wouldn't wear for business then it's okay for a wedding. For example, I've worn my black Corneliani with white pinstripes to a wedding and I don't think it looked a bit out of place; but, I wouldn't wear that suit for business.
As far as interviews, while there may not be anything wrong with wearing a pinstripe suit for an interview, I personally wouldn't do it because there is less risk involved in wearing a solid suit than in wearing a patterned suit. If you don't have a solid suit then fine, but if you do, better safe than sorry when it comes to interviews.