I didn't realise there are 3 Chihuahuas!!! I can't ever imagine a Basset Hound hurting anything, especially your nieces and nephews, in fact, quite the opposite is true of Bassets (unless someone treats them really very badly and even then they would be too soft to retaliate)!!!
Mine and my family members' Bassets have been all brought up with babies and children and none of them, including rescues of unknown origin, have ever put a foot wrong! Just have a look at these videos to see the Basset nature with young children and babies!