ok proper Evidence of Hashirama :
Powers fairy tail like the Sage of 6 path...
Strongest Shinobi (madara wasn't on his level)
Defeated the EMS Madara + the strongest tailed beast.
Possesses the same power equal to edo madara.
Has been called the "Best ninja" by Kabuto (Episode 256)
And has been stated by madara (who was alive during sarutobi's time) that only Hashirama can stop him..
Proper evidence of Sarutobi:
1. was known as the God of shinobi.
2. Mastered alot of stuff which made him known as the Professor
3. Stated to be the strongest Hokage leaf had by Iruka
4.Strongest Kage of his time. (not when he cameback from retirement)
Thats only 4..
You mentioned the Edo battle.. Yet i do recall Sarutobi getting his ass kicked and then loosing his life..

the Edo served their purpose their for Oro won.
The person who left the battle alive was Orochimaru. So he won. Using a suicide move on someone is not defeating them. Hiruzen had no choice.. ;l.
Also, the battle was just to show that he could do stuff even in his old Age..But it did not represent Hashirama and Tobirama's true fighting power.