An overall floor plan would help with advice as your descripotion does not really tell us where the new rooms would be exactly and where the would be. But of course the flooring should match pretty much everywhere but the kitchen and bath which be tile. The kitchen can be hardwood as well. Mu only concern is the hardwood you currently have is prefinished so it may be a bear to refinish but the hardwood should all match in species and color.

Always best to have one type of flooring in spaces seen together . Bathhrooms and bedrooms can have another type for sure .

If you're refinishing all your floors, I'd get a price for that and consider replacing all with wider engineered lighter toned European Oak.