Never confirmed by Gunn. There is an Easter Egg scene where it shows all the different species Ego has been with and one of them looked like Mantis. Most of us don’t think so because of what happens to Ego’s children when they do meet their father.

Potentially. I mean it makes sense that he is. Why would he breed with a Mantis species, have a Mantis spices child, but also take Mantis as his servant? It just doesn't make sense. So I believe she is.

It is not confirmed

It is not confirmed yet but it is very likely to be true.

Thank you all☺️