Yellow-browed Warbler can often show a faint median crown stripe, especially in the second half of the winter, so be careful if you are relying only on this feature.
This bird is tricky because it is partly hidden by the branch. I don't think that the median crown stripe is obvious or neat enough for Pallas's, which would also be yellower on the supercilium and darker on the eyestripe.
I would also expect a Blyth's-type (Goodson's or Claudia's) Leaf Warbler to have a more obvious median crown stripe at the rear. Also the structure seems wrong to me for these species (e.g. head too large, bill too small, tail too short), the lower mandible looks too dark and the great coverts are quite dark-centred.
Two-barred Warbler also shows two wing-bars, but that should never show any hint of a median crown stripe, and the dark centres to the greater coverts also don't fit this species.
For me, the features visible on this bird are all consistent with Yellow-browed Warbler, one of the individuals showing a slight crown-stripe.
