Unity wrote:

The setting says it uses these materials quite a bit in armor, but I am not certain as to how viable this is in real life. How would diamond hold up to laser fire or kinetic weapons? Flame? Same question for fullerene.

Diamond is incredibly strong but somewhat brittle - hit it sharply along the right cleavage plane and it will crack. Technically, the hardness is very good but the toughness is somewhat mediocre. However, if you can grow diamond in any shape you want, you can create composites that are very tough. Imagine layers of diamond with planes oriented in different directions, held together by a semiflexible matrix of graphene, fullerenes or some other tough material. This also avoids the nasty potential problem of diamond splinters. Diamond is not very flammable. It is an excellent heat conductor, and it takes some pretty high temperature (848 C) to make it burn in air. Compare to iron, which is also possible but hard to ignite (steel wool has a big surface area and burns readily, steel doesn't). Fullerenes are also really flammable in free form. But when woven into sheets, fabrics or composites the problem goes away. While diamond can withstand a lot of pressure and tension, fullerenes handle tension well and allow flexibility. Some armor research today deals with gels with fullerenes, where sudden impacts have their energy carried away by the fullerene tubes but normal motion is not hindered.