Your ignoring the fact that Obito had a 1 and a half hashirama senju clone body with it's chakra signature as well as an uchiha chakra signature... Meaning Obito had a Hybrid chakra signature which is something any sensor would have trouble determine who the user is... If the sensor knew obito before his augmentation of hashirama and the uchiha power increase of the MS...
Not to mention, obito before that was a calm uchiha with a clam uchiha chakra aura... As opposed to the new uchiha chakra signature that was more the doubled in power and very dark and full of hate... Making Obito a completely different person with completely different chakra, not even including the hashirama augmentation as well...
SO I wonder why Minato would not be bale to tell who Tobi really was, much less anyone else... And I never said minato could sense other's chakra like High level sensors... He can give away and sense his own chakra while creating seals that give of a signature for sensing as well... That and sense the number of people and even seem to tell the difference between real and Kage bushin's by touching the ground.
Barely keep up with Obito??? What manga are you reading??? Even with Obito's own uchiha power more then double in power. The one and a half hashirama senju body augmentation made Obito very fast, strong and durable.... But, Minato's physical speed was still equal to obito's supped up speed... And his FTG was faster then Obito's reaction time and time space KAMUI jutsu as well...
And somehow Minato barely kept up with obito... Again, what manga are you reading here???
And how is what minato can do times 10 not beating hashirama lol??? That is way way way over hyping hashirama... And WHY??? Because he has allot of power and can produce attacks on the scale of a bijuu??? SO what!!! Minato already owned the kyuubi and he is the strongest of the bijuu other then the juubi itself...
And if Minato can summon away the kyuubi and it's huge attacks then hashirama and his are just as easy if not easier since they are not as strong... So How can hashirama beat Minato again? Because he can change the terrain with his brute power... SO what, Minato can transport hashirama to any terrain he wants with already strategically placed seals (like he did with the kyuubi). ANd if Minato transports hashirama to a body of water, then hashirama is not even half as strong as he is on land...
Basically, all Minato has to do is use his FTG (level 1 and 2) along with his t/s barrier jutsu to overwhelm hashirama... Because hashirama has no counter or way to negate minatio's T/S jutsu...
And with the use of Minato's summons (Gamabunta, Hiko and the other boss summon) Including the sage frogs which allow minato the use of fire style, oil, water and wind coupled with the sensory abilities, frog su nature energy wielding and frog song... Hashirama cannot possibly win...
Not to mention that Minato's chances of being able to use SM by fusing with Fukasaku and shima as a frog contract user like the two other frog sage's and the fact that hashirama was not supposed ot have SM ,but looks like kishi can easily pull jutsu out of characters asses making Minato the most likely candidate to be a sage too...
LMFAO!!! Hashirama would not of gotten past this point
http://www.mangapanda.com/93-55464-9...apter-502.html
and Konaha would have been destroyed if he was there instead of Minato...
Or does hashirama have unconfirmed magical Time space jutsu??? Because Hashirama would have been sucked into KAMUI and died later from starvation with no way to come back... FKAT, swallow that and digest it!