All SM are different. The properties the different animals give is obviously different. If toads, slugs and snakes gave the same SM attributes, there'd be no reason for there being three distinct ones.
Anyway, as far as I can see, in relation to the others. Toad SM gives strength. Slug SM gives healing. Snake SM gives, possibly, heightened agility as kabuto seemed far more agile than naruto(don't mistake naruto's sensor enhanced dodging/heightened reactions with kabuto's agility). while all of them give sensing, defence boost, power enhancement.
hashi is using the dragon sage which he taught the toads and was modified to toad sage and was taught to naruto
MY THEORY,INSULT AND I'LL REPORT
For one Hashirama's SM could be completely unique to him since there's no connection to any of the three places where Sage users learn their SM from.
Oh,so you can explain better dummy, well let's hear it,I told you mine,and a sensible person would prove me wrong without barkingThis theory is sh!t without any proof. Hashi and toads have no relation to each other, hashi didn't even display any toad summoning jutsu.
Go report it i don't care...
We don't know that. For all we know it's the slug SM.
Hashirama just learned it one day meditating in the woods. He could always feel the natural energy in the air.
Except Hashi has'nt shown any slug traits,every SM user we've seen in the manga have had traits from the place where they trained in.Jiraiya and Naruto had toad like traits especially with the former and Kabuto had serpentine traits.