Thanks all for you quick replies. He is a Visla cross (not sure with what), and according to refuge came from a family with 3 young children (moved and could not take him with them)- but really- we will never know for sure.
Yes- the children will be supervised at all time, and I will keep in mind to wait 6 weeks before fully feeling that we "understand" what he will be like.
Small steps here- we have wanted a dog for many years however wanted to wait until the children were out of "baby" phase, and feel we are doing the right thing to get a dog that needs a new home instead of puppy....
I have had dogs in my youth but not for the last 15 years, so its been a while.