Carbon fiber's serious business, apparently.
Don't be so specific.
I would instead put forth the possibility of using a silicon macromolecule instead of carbon fiber, as we could likely create something much tougher than carbon fiber, which would be important in high performance bone structures.
I'm not terribly familiar with what makes carbon fibers so string, so I'm turning this over to the more chemically-apt members of the forum.
Come up with a chemical (or a description of it) and I'll come up with an opinion on if it's feasible!
Also, in case none of these pan out particularly well, I would like to recommend making the human waste system more efficient with everything, seeing as how resources are going to be scarce, and would also recommend a side project of creating hardy crops that provide the necessary nutrition that can survive all the planet throws at it.
I think that that's pretty well-agreed.
EDIT:We could even incorporate the necessary silicon into the plants, and before you ask where they would get it from consider that most things we'd consider dirt are made of silicon oxides.
The necessary silicon for what?