Looking at this LTT video around the 11:30 mark you can see that they’re packing the dual M.2 boards without putting them into any sort of shell. To me this could hint at being able to purchase the board and then install it into the expansion bay shell. If that is the case, when you get the expansion bay shell, you’d still have the option of getting that extra storage, even though it’s not an option currently when you order. Looking at my own expansion bay shell, there appear to be mounting points that line up with the board shown in that video as well, which could be a further hint. Obviously I can’t know that’s their plan for sure but it’s interesting to think about.
I’d assume so considering that that is after all the point of the shell (to be a shell to put a variety of potential modules in), the fact that Framework previously stated “you can put an Dual M.2 SSD Holder Module in your Expansion Bay Shell”, and that the design files that they released for a prototype of the dual m.2 board say “This is a reference design of a Dual M.2 SSD Module that goes in the Expansion Bay Shell.”