I've used calci sand for my adult beardie for a couple years so far with no problems at all. Once they are adults they should be a lot less "clumsy" compared to when they are babies. The only thing you have to worry about is them accidentally eating sand with the crickets but again they arent as clumsy as adults. There is a risk of being impacted if they consume the sand but like I said I have used it for a few years now and its all good. It is a lot easier to clean etc... and looks nicer for a display tank setup vs. ugly newspaper. I'm no expert so use it at your own pets risk and be ready to shell out vet bills if he/she becomes impacted-->which can lead to death BTW!
As for keeping two snakes in one enclosure, I have heard many opinions back and forth about this topic. I just recently bought my first ball and I asked the breeder what he thought about the topic. He said as long as you keep only ONE male you should be perfectly fine as long as they have room, separate hides and fed separately. Again I'm new to balls but he's a breeder and I've seen people who know quite a bit that do the same.
People who say there is absolutely no benefit to keeping more than one snake per enclosure, well there are benefits like less space taken up in your house, less supplies like bulbs, heat pads, water dish, bedding, temp guages, etc... This to me would be a plus if it was actually healthy for the snakes. If it is unhealthy for them and you actually have proof of this or have personally experienced negative results I would be glad to hear the stories you have.