Hiashi would've been the one to save hinata and naruto in the war , handing neji the title if hyuga leader on the spot.
Then he probably would've had alot to do in naruto "The Last" seein that the otsusuki and hyuga had alot of internal afairs that needed to be fleshed out.
Toneri would've had a twin sister (main branch ) to add drama and balance ,
Hamura would come to neji as the tru byakugan heir an given him his chakra for real this time , without it bein as confusing and "useless" as with hinata.
After toneri and his sis are defeated , naruto would've asked them to return to earth which toneri rejects while his sis accepts the invitation.
Chapter 700's version of neji would've ended up with the sister and be showcased in training with his child who would look like a tiny hamura due to his parents.
In terms of clothing i could see him sporting somthing similar to wat hiashi wore , only it would be colored green/black to rep the "8 trigram" with a yin/yang sign on the back , he would've had the same hairstyle.
In terms of his childs characteristics , i see him bein a mix of early part1 neji with a bit of itachi.
Its also good to note that the kid would most likely be by far the strongest kid in the current generation, and would be the best rival/pal for bolt and would be a great not so obvious love interest for sarada.
