If anyone is interested, I did see Snow Finch and Alpine Chough, but predictably not Wallcreeper. We stayed in Grindelwald for two days, but I think anyone who is planning to visit for such a short period should bear in mind that low cloud can be a problem. The first day we only went as high as 1955 metres to a place called Schreckfeld, due to concerns about low cloud. I did see Alpine Chough, but only in one flock which disappeared fairly quickly. I did however see Golden Eagle, Water Pipit and the central European race of Ring Ouzel, but it there was no sign of Snow Finch.
The next day we went to Mannlichen which is 2230 Metres and had good views of both Alpine Chough and Snow Finches, but they were not noticeably tame. The only other birds we saw there were more Ring Ouzels and a Raven, but it was worth going for the view alone.
The important thing to note for visitors looking for these Alpine specialities is that you need favorable weather, and you need to get as high as you can. I have heard people say above 2000M for Snow finch, and that seems to be borne out by my experience.