Wood release, is only special to Hashirama. Tobirama a another pure senju didn't have it. Nor did any other person in history.
And are we forgetting Sakumo Hatake? Minato has pretty nice chakra reserves. Not every senju had Tobirama or Hashirama's reserve you know. Just like it says the Senju clan was diverse. ;p
Wood release wasn't typical to Hashirama, but someone like Yamato was able to use it too, just because he had senju DNA, so why can't I say that someone from Konoha must be capable of using it, if all of them have their origins in senju clan? Tobirama and Tsunade never used it I agree, but we can't deny that one out of three known senjus was able to use it, and senju clan actually had name as 'senjus of forest', so there is a probability that many others were capable of using it.:yeah:
On Minato's chakra reserves, I would like to say that his chakra reserves were decent but weren't on Hashi/Tobirama's lvl.
On Hatake clan, even Kakashi's chakra reserves were naturally low, so as so that sharingan used to wear him out. So no, I don't see the possibility of Hatake or Namikaze clan coming from Senju clan.>_>