They're not putting the asteroid in orbit, they're using their perfect knowledge to point a laser at some specific point in space such that the cotton candy asteroid just does that (because they can predict the position and velocity of every particle in the universe). If we're gonna be perfect science dorks about the magic-device-driven hypothetical, group A has to fail because they violate conservation of mass unless the resource generator is actually teleporting those resources from somewhere else, and then they're breaking c (plus they're probably also colonizers, now).
Perfect knowledge means perfect prediction. Group B can build a device to perturb the state of the universe in such a way that an asteroid made of cotton candy enters perfect geostationary orbit, if that's what they're into. Infinite raw resources only matter if you've got something to do with them. Knowing more means doing more with less.
Talibanderites? Now this I gotta see!