I agree and excellent thread
Three possibilites why All Naruto, Minato and Obito resemble The Sage of six paths
1) Uzumaki Sealing techniques or simply same as Sage's used cause Naruto, Obito and Minato to looks like Sage of six paths
2) Sage of six paths devided his remaining chakra and divided placing in each tailed beast, or simply while creating them some of Sage chakra infused with Tailed beasts. Whatever one is right, the point is Sage chakra may be resident in Tailed beasts cause their Jinchurki to resembles Sage of six paths... But here is plot hole: "Why Killer Bee as Perfect Jinchurki of Gyuuki doesn't resemble Sage of six paths..." I have only answer for it, maybe Kurama has the most part of Sage's chakra sealed in it in compare to rest of tailed beasts.
In short, Kurama chakra alone is enough to manifest Sage's appearance on Naruto, and eight tails has not enought to manifest Sage's appearance... However Obito has full Seven tailed beasts so that why he resmbles Sage of six paths to such degree..., besides he has still Nine tails chakra from Kinaku and Ginkaku...
3) Combination of both 1) and 2) is required for shinobi to begin resemble Sage of six paths....
It requires Uzumaki sealing techniques(Specific ones) + Sage's chakra sealed in tailed beasts
Personally I believe in
THIRD OPTION TO BE CORRECT,
what do you think guys, Sir Derp Obito ?
Could it work ? It seems that Just using same sealing arts could be not enough as all Uzumaki could looks like Sage of six paths, Same with being just Jinchurki as Killer Bee proves that he doesn't resemble Sage of six paths.
But All Minato, Obito and Naruto used Sage of six paths's sealing techniques + has Sage's chakra sealed in Tailed beast as Jinchurki they are, with Minato just having chakra of Kurama... as exception
Naruto = Has Tailed beast(piece of Sage chakra) + used Sage's sealing technique
Minato= has Tailed beast chakra(piece of Sage chakra) + used Sage's sealing technique
Obito= Has tailed beast(piece of Sage chakra) + Used Sage's sealing technique
CONCLUSION:
Formula is Sage's appearance= Sage' s sealing techniques + Sage's chakra present in Tailed beasts