I would not home a rescued dog with small children. There is no way of knowing whether its past experiences, with children or indeed any situation at all, have been positive or negative ones, there is no way of knowing what, if anything, is its trigger point. I would only ever have a puppy, reared in a home and loved by a breeder I either know, or know of through other happy owners, where I can be absolutely certain that when that pup comes to me at 8 weeks old, all its experiences since birth have been wholly positive.
And I would not home any dog with a two year old child, who is far too young to respect the dog, and to understand the potential for a split-second reaction to be catastrophic. Let the child grow up and learn how it needs to behave around dogs, and maybe fewer dogs would end up being rehomed when their unacceptable behaviour was triggered by the unacceptable behaviour of the child it was expected to tolerate.