Great! Very happy it helps you!
First of all, I love all shades of blue, from very light to very dark, and grey too... so sometimes light blues in Hermes are very close to grey..
The Kelly I have is very appropriate in Bleu Lin because it's luminous yet not so light, so not as heavy maintenance for an every day bag. If it was lighter I wouldn't use it so regularly. I wear jeans almost every day so this is stunning with jeans.
Bleu Brume is a color for a bag I will not use daily (but this is just me), hence why I bought my Constance in Bleu Brume, the Constance is a bag more on the dressy side for my lifestyle, I won't use it on a daily basis.
Now, if you ask me to chose between Bleu Lin and Bleu Brume, I would say Bleu Brume every single time, it is a more desirable color, very difficult to get and I do love light blue bags, it's my "pop of colour" because I am not someone who will wear a bright bold colour, but a pastel blue, absolutely!
The Bleu Pale that you see on the Picotin is actually almost a light grey and Bleu Brume is much brighter and unique.
Not sure they even do Bleu Lin at the moment though...