I’m not familiar with the shovel nose snakes, so I don’t know anything about their care or how they would do in an educational setting.
The sand boas are an option, but I was under the impression that they tended to be shy snakes that didn’t care for handling. This is from research I did a few years ago, so it may be outdated. I bow to whoever actually keeps them to provide that info.
I’ve recently been looking into Anthill pythons myself. From my research so far, they are calm pets and the smallest of this group of pythons, which include Childrens and Spotted pythons. It doesn’t appear that their husbandry is too difficult, but from what I’ve read so far they do need about a 95-100F hot spot. So a bit warmer than the bp’s but not too difficult to acheive I would think. The Childrens and Spotted pythons may also be an option...care for all three appears to be very similar.
The Candoia are another possible group, particularly if you go with a male. My Solomon Island ground boa is about 18 years old and around 2 feet long. He’s also very tolerant of handling. A possible bonus is that they have keeled scales, which feel very different from any other snake I’ve held. Anyone else who has held him has always been captivated by how he feels. Many of these are wild caught, as mine was, but you can find captive bred animals or long term captives that are used to handling. I would suggest a yearling at least as neonates are very tiny. Care is pretty simple as they like it cooler...ambient temps in the upper 70’s to 80F. A lot of care sheets don’t suggest a hot spot, but I provide a basking spot of 83-85F which he will use after feeding. The rest of the time he’s in the cool part of the cage. They also love to soak, so a water bowl large enough for that is needed.
I know there are a few others, because I’ve been looking into smaller snakes recently. I just can’t remember what else I’ve looked into that didn’t make the final cut for consideration as a pet.