Peter Quill and Mantis aren't siblings in the comic world. There's no established connection of that kind. They have their own unique roles and arcs that don't involve being related by blood.
Definitely not. In the comics, Mantis and Peter Quill have no sibling bond. They are separate characters with their own unique adventures and interactions within the comic world.
In a Peter Parker and Mantis fanfiction, their powers could also combine in unexpected ways. For instance, Peter's spider - sense could be enhanced by Mantis's ability to sense the emotions of those around them. This could give Peter an edge in predicting attacks, not just from the physical movements of his enemies but also from their emotional states.
One interesting aspect of Peter Parker and Mantis fanfiction could be their interactions within the Avengers compound. Maybe Peter is showing Mantis some of his latest web - slinging gadgets, and Mantis is fascinated by the technology, which is so different from her own powers.