1. Yes, the hub will be a flip/flop hub ie fixed on one side - freewheel on the other
2. We will not offer a bolt on style fixed cog hub since Level is already manufacturing a bolt on style hub and they have patents on the design.
3. Why the internal splines? Well, the photos you are looking at are prototypes. We took several prototype threaded fixed gear cogs we made and machined splines into the cogs for the show. Production pieces will not have the internal threads. It would be nice if it could work with either system, but the minimal thread contact on the splined cog would strip a threaded hub shell.

I'll check back to see if there are any additional questions. I usually do not jump into forum conversations, but it seemed some clarification was necessary with our product. If you would like to contact me directly with any questions, please feel free to do so. My e-mail is lynette@whiteind.com

Thanks
Lynette