I think this is White-browed.
It's bizarre if e-bird says it's not there. Both experience and the books make clear that in the two locations mentioned it would be the default species.
One point about Rüppell's is that the central tail feathers are black, not olive brown. The OP's photo three clearly shows olive-brown, the same as the back.
Unfortunately I don't have many photos showing the tail clearly; I attach a couple. One shows a White-browed from Masai Mara where the central feathers of the tail can be seen to be like the OP's photo and not black. There is a second photo from Manyara in Tanzania showing the same thing. (I have a couple of photos from Nakuru, near the OP's locations, but unfortunately because of shadow and digital camera quality in 2008 the tail colour is not clear.
Also Rüppell's, as 'Birds of East Africa' says, 'is more of a highland forest bird than White-browed' and the habitat as seen in the OP's photos is clearly better for White-browed.
I attach two photos of Rüppell's (same bird) from Ethiopia which show the black tail. One photo with light shining on the tail emphasises my point, because it can be seen that even in bright light the tail is clearly black not olive-brown. Or so I think, at least.
On the supercilium, the Rüppell's we saw in Ethiopia had a supercilium that was narrow in front of the eye, but much wider behind. I don't know if this is a feature or an individual thing. ('Birds of the Horn of Africa' has the same text and illustrations as 'Birds of East Africa' so it was no help here.)
HTH
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