I am curious to see how the flowers work out. Lots of nooks and crannies there. I would think it might be best if you could somehow leave (or cut) the base of the inflorescence so it is exposed to the air and allows at least some of the moisture to leave the center through that little highway before it dries up.
You could mold some resin into the shape of the branches (create a mold and then fill that with some long-lasting material, plus structural support) ... allowing you to make the current shape and texture of the branches permanent (for a table). I don't see how you could use the leafy parts, except maybe through sculptural approximation.
On top of the issues with moisture, you might have a real structural issue if you try to use any of that stuff to hold up a table, especially as it deforms upon dehydration. It's not yet woody, especially not at the top. So the mold concept might give you a real advantage in this sense.
I am no artist, just trying to imagine how you could make something useful that lasts, given the inspiration of the plant materials present.
