Would my top front teeth have gum grafting done before composite resin bonding to fill in gaps? Showing tooth roots as an adult.

Yes. Yes, grafting before, grafting can adhere only to natural dentin or root surface.
Difficult to say. Without an examination to determine what is occurring and offer you proper advice. I would respectfully ask that you ask your dentist this question so that he/she can give you a proper and complete answer to this question as it applies to you.
Gums first. Gums get grafted (or repositioned) before final restorations are done on your teeth.
Where are the gaps? If the gap is at the gum line, gum surgery will come first. This will minimize or eliminate the gumline gap. If the gap is between your teeth, probably gum grafting first there as well. You would not want the bonding to interfere with potential root attachment.The final gum position will dictate the cosmetic finish. You may want to consider invisalign to close gaps, works well on good candidates.
It depends. Exposed roots can be covered with either composite bonding or tissue grafting, depending on the severity of the defect, esthetic needs, and/or root and tissue morphology. We typically don't do both unless neither won't solve the entire issue. Seeing a photo of your case would help answer the question. Usually one or the other is chosen, based on desired outcome, cost, and convenience of treatment.
Generally graft firs. Yes, you would like to have the soft tissue graft heal up and know the architecture of your gums before bonding is done, to make the best esthetic outcome.