You should look for a Prosthodontist who has specialty and trained in crown and bridges, restoring implants and full mouth reconstruction.
You have to get bondings before fabricating a mouthguard. If you get your mouthguard first, It will not fit in your mouth after having bondins.
Having pain 2 weeks after implant placement is not a good sign. See your doctor as soon as possible to find out reason of having pain.
Implant placement can be done either at the same day of extraction or after few months. Bone graft depends on bone quantity and It can be evaluated by taking a CT scan. It is not recommended to place an implant couple weeks after extraction.
If your crown is OK and margins, contours, contacts are acceptable, root canal can be done through the crown. It has to be evaluated by your dentist.
