This has happened to the most cautious of owners, so while your concern is great, try not to beat yourself up even more! I am not a breeder, so am not qualified to answer most of your questions. I'm sure one will be along before long....so I will only comment on what I know. I do know that males do not need a role model; although some may not be as confident at first, and may need a little help, they basically instinctively know what to do, without having to observe other sexual activity. Technique may vary, but they figure it out. And being related makes no difference. Their sexual behavior is based on instinct alone. Mother, sister, aunt, etc....doesn't matter. This is not a perverse thing, it is just how dogs are. Also, inbreeding is a breeding technique sometimes used by some experienced breeders to bring out good (or bad) traits and conditions--so inbreeding does not necessarily result in "deformed" puppies.
Sorry I cannot comment with any authority on the other questions!
I know you will get some good advice here.