Kind of quick if it ends in just 5 more chapters? Now I am not disputing this source I think this is legit. I am just saying you need either a good 40 page final release or at least two full chapters dedicated for the ending or epilogue right? So that means about three chapters of fighting? That is very quick!
I don't think I remember even one single fight in Naruto that is 3 or less chapters not counting very small side fights etc. I am probably wrong and I only started the manga during the pain invasion arc but still. Even most of them where over 3 chapters. Personally I hope we get 1-2 or extended chapters with at least 30 pages if not more. I expected this fight with Naruto and Sasuke to be over 8 chapters minimum with just the fighting sequence.
I find that Anime/Manga are horrible for showing what happens later. You often only get one chapter to wrap things up and show minor things about the future. When I feel a manga that has gone on for 15 years need like 50 pages of content to show what happens to the characters we have all been following.