I don't think he is from Saria. Then I rather think he's from Mido's line.. he narrow eyes and pointed hair..? And Saria was an Forest Sage...
Another reason is that,, did you notice that all the leaders in hyrule in
OOT. is an sage, Darunia and Ruto is some kind of leaders. And Impa too. Nabooru is the leader of the gerudoes, if it weren't for ganondorf. only saria isn't a leader??? so there could be a posibility that Mido's line was a sage. Just that Mido wasn't awaken as a one. though, if this can fit together..
But then again. It may be that Fado's ancestor isn't mententioned yet...