I hate carbon fibre, in a good way. I don't work with it much but I know how much of a pain it can be. Are you planning on vacuum bagging your mold? Folding CF won't affect it unless you crease it, CF has huge tensile strength but zero compression strength (that why we use resin) so you want to make sure that you have strands running in as many directions as possible along the longest possible path. This will make sure the loads are distributed evenly along the whole length and in all directions.
For a few things on aircraft we can design a part to be strong in one direction but weak in another, for a 'flapper valve' for example, but you don't want this in your tube so symmetry is key. Also using foam, 'air weave' or 'honeycomb' in a 'sandwich panel' structure will increase rigidity without adding much weight but will increase the bulk of the tube.
Twill looks pretty but 1x1 is easier to use over smooth shapes and cheaper, for a basic laminate I usually lay up 2(1x1)-airweave-1(1x1)-1(2x2) keeping the 2x2 as the top layer because it's 'pretty'.
It sounds like a great project, keep us updated and I'd be very interested to see pictures
