Thanks very much for sharing. Having done one of these hills on a wet day, and then two of them on a perfect day in May, I'm impressed at all three of them in claggy winter conditions!
I can confirm that there is absolutely no point in trying to find the east summit of Beinn a'Chroin unless it's clear. It's only worth visiting for the views, and there is quite a dip between the main summit and the east summit.
I can also confirm that taking in An Caisteal would be no harder than missing it out. The terrain down into the glens either side is lumpy, steep and confusing. For my photos in nice conditions, see
https://www.walkhighlands.co.uk/Forum/viewtopic.php?f=9&t=80675It's an interesting point about decision making. I wonder if the human mind is more sophisticated than we think in these circumstances and can process a wide variety of risk factors, some subconsciously. As you say "I know I coudn't face climbing back up again, feeling that I might still not find a way, so I took a (just about) 'calculated' risk."
I also agree with the various points about transition summer to winter. In summer these hills seen quite friendly, and the paths are obvious (although I don't know about the bealach east of Beinn Chabhair). But in claggy winter conditions, these hills are a good example of how lumpy terrain can be really hard to read and to relate to what the map and compass are saying, and the steep slopes can be dangerous in unexpected places.
Well done - every trip into the hills is a lesson!
Tim