Well, a few things.
1) You're probably going to have trouble buying sexed, JUST female, goslings. Most are sold either straight run or in pairs.
2) Ducks are not geese. I know! Newsflash! But seriously, handling and raising them is apples and oranges to one another. They are both waterfowl, but that's where the common denominator ends. Their diet is different, the amount the eat is different, the amount they poop is different, they way the interact with each other and people is different, so on and so forth.
3) It is NOT a good idea to imprint ganders onto people.
4) The notion that geese will be "fine" with children if they're raised with them is absolutely false. In fact, come breeding season, the closer they were to the children while raised the more likely they are to attack.
5) Just because your geese learn to respect your children does not mean they are trustworthy with other children. Geese are strong, they do not stay cute, fuzzy goslings very long and they should be taken seriously as juveniles and adults. The damage they can do to a small child is no joke. Last time I, as an adult woman, broke up a gander fight I walked away with a bruise the size of a salad plate on my lower leg from one hit by one of the ganders.
6) Know that your geese learning to respect your children is a BIG "if". Especially during the breeding season. Especially if your children are young, small and/or timid.
7) Obsession is a very bad place to be coming from to purchase an animal. Geese can live upwards of 20-25 years. This is not a snap judgement to be made. It is a long term commitment. Do some more reading and research. Read credible sources, not just message boards where you get to fill up your hopes with funny anecdotes. Do those things happen? Of course, but those stories leave out all the pragmatic, day-to-day responsibility of goose ownership. You're excited on your own, you don't need help with that. You need help seeing the reality of keeping geese in your backyard.
Good luck!