Friend with young doberman visiting....how do we introduce our pets and my children safely?

A friend will be visiting with their 5 month old female Doberman and will probably be staying for a while. I have a male Cavalier King Charles Spaniel who's about 8 months old and three children aged 7, 5 and 2. I was just wondering if anybody could tell me how best to introduce the animals and my children? And is it a good idea to keep the dogs on a lead in the house with the kids around just to be on the safe side? One of my children can be a bit too rough and I'm not too sure what to expect from a Doberman as my Cav is very used to them...also my Cav and kids have very excitable energies, don't know if that would make a difference? One other thing...will be getting my Cav neutered soon should I do it before they get here? Thanks in advance...