I advice to go for re root canal treatment. it will save yr tooth. Infection is there [ in apical area], so before implant surgery u have to wait for few months. i give implant as a last option.
I would prefer placing the implant in the proper position rather than placing it at a 45 degree angle. The biting force could potentially cause a failure of the implant.
The best route in my opinion would be to extract the tooth and do bone graft on the same appointment. 4-6 months later place an implant. I would not suggest to move all the back molars forward due to distance of the space and future bite alignment!
