The part I bolded does not exist. I'm not being mean or discouraging, just honest.
Snakes can not be left unattended at all unless they are secured in their enclosures.
They are very fast and extremely good at hiding when they want to be. In addition to losing your new pet, it can also get hurt quite easily by getting stepped on, tripped over, something dropped on it, falling even a relatively short distance, trying to fit into a too small space & thrashing, knocking things over onto itself, etc. It is much easier to kid proof your house then to herp proof it.
It is very possible to have both small children & snakes at the same time if the proper precautions are taken & the children are taught proper handling & respect. Snake bites are Keeper error, they happen when
we do something wrong.
I grew up with various reptiles and my daughter was born into a herp keeping home. Because I was unbending about proper handling & respect towards them we only had one single incident with all the various critters we had ~ she dumped our new tadpoles in the turtles' tank
I never once had a problem with her and my 6 & 8 ft (apprx. I quit measuring them) boas, even when she was a toddler.
All the snakes listed are pretty good for beginners. Personally, if not a boa (I'm predominantly a boa girl), I'd go with a cornsnake. Their length is offset by their slimness, they're easy to care, stay on feed well, come in a vast variety of colors/patterns, make great display animals, are generally easy going & once they're old enough they tolerate handling well.
I'd also recommend checking out your local reptile show if you have one. You'd get a chance to talk to breeders in person, pick up some great tips & the show I go to has a better variety than our zoo so the kids could have a blast