no we dont. the anime translation (which is usually accurate to VIZ) never mentioned an ambush, that was a mangapanda fu ck up.
also how can someone whos supposed to be this godlike sensor get caught off guard anyways.
we HAVE to go by feats because hype alone is unreliable and contradictory. look at hiruzen. his hype is all over the place, and is mostly dictated by fodders. eg. if hiruzen knows all konoha jutsus wheres his sharingan and byakugan. if hes god of shinobi why is oro/suigetsu etc no longer calling him this. feats are cold hard evidence of a person's power which cant be disputed or refuted except through retcon
are you really suggesting tobirama killed all 20 of his opponets then randomly died himself? he wouldnt do that for one, hes too prideful, and second his reign was short lived. he barely had enough time to create the academy and police.
we know that there arent a "crapload of talentless fools" in a village. theres usually up to 10 extremely strong elites which can then guard the kage. and then theres all the unique bloodline users and clan abilities. depending on what village third fought, he may have had to go up against magnet release and hozuki clan