
Generally I'd introduce on neutral territory ... which in my case has been at the breeder's place. When home I put pup into a crate and allow older dog free range, then swop over, that way they get used to each other without the worry of harm. When all let out together, I do allow the older dogs to tell the youngster off, if needed, but I am totally confident that no harm will come to pup, it's just noise. You will have to access that one yourself.
I am a firm believer in that if ... you think it's going to go wrong, then it will. If you stay relaxed, then hopefully your staffie will. Remove all toys and anything of value to the staffie, so no chance of a squable over that.