HBG are definitely great for kids. If you are going to be consistently feeding the fish, I would possibly consider them. However, I would not stock them until after your SMB are at least 6"-8" in length. I'd want them that length to make sure they can effectively prey on any offspring the HBG may produce. Their production of offspring will be limited at they are generally 90-95% male, however, they'll still produce some and you don't want a large crop of F2 and subsequent generations taking hold in your pond.
If you aren't going to be consistently feeding your fish, I wouldn't stock the HBG as they will strongly compete with your SMB for food resources. Honestly, in a private pond of 2 acres, if managed I think you can still produce a fishery where children can catch quality fish without much effort without the use of HBG. YP would be rather easily caught and within a year or two, your SMB will be reproducing if you place to correct rock structure for them to spawn on. In all likelihood, they'll produce too much and you'll need to remove a fair number of fish. Something the kids will love to help with.
Are you on the southern end of WI? If so, RES should work for you. In ponds where they aren't in competition with other sunfish species, they often are far easier to catch. They too could be a great source of fishing entertainment for the children.
Let me know if you must have HBG as a component of your fishery and I will give you my opinion on a stocking strategy.
