With the caveat that I have no first-hand experience of Aberrant or Hume's Bush Warblers (only seen Brownish-flanked), surely no.1 is Aberrant, with that strong loral stripe, greenish upperparts and yellow cast to the underparts. This is apparently more typical of Himalayan birds. It must be a juvenile with that much yellow on the bill, although more advanced in age than the birds in no.2.
As for nos. 4-5, I see no reason to suspect Hume's. There's quite a broad loral stripe, the crown is quite dull (concolorous with the mantle) and there are no rufous tones on the flight feathers. Again it looks a bit too yellowish on the underparts for Brownish-flanked, but I wouldn't like to say it's Aberrant with any certainty.
EDIT: Forgot to say I agree with Rufous-winged Fulvetta for no.3.