There isn't really a best order of building the family, but I would start with the Dad (since it takes a while to win at bingo). Next either the Mom or Boy and then the other. Last would be the Tyke (since you have to have all family members in town at the same time to get a gift from him). You only get 1 gift per Tyke, so it would have to melt (lasts 4 days) and have all family members again to get another gift.
Remember with the SnowTyke, how well-made the snow family members are made determines what gift you get.
Only SnowTyke is well-made---sleigh
One other of the family members well-made---small igloo
Two other of the family members well-made---snow bunny
All family members well-made---snow family matryoshka (nesting dolls) my favorite
Good Luck