Will gum graft help me prior to conventional braces?

It is better to have a gum graft regardless of future braces From the pictures, the gum tissue in the areas you have mentioned  look very thin/ receeded100% root coverage will not be possible due to the amount of bone loss between your teeth ( loss of tissue fill between your teeth is an indication for this bone loss) .  The gum graft ( with tissue harvested from the palate as your best option) will be mainly to increase the thickness of your gum in the area to prevent further bone loss and recessionif tooth 12 is loose, you might want to have it splinted to adjacent teeth to reduce it's mobility. I recommend you see a periodontist for evaluation. He/ she can help you with gum grafting. Also to evaluate you , as I am concerned with the amount of bone loss and tooth monility  , you might not be a candidate for more orthodontic treatment.