can you explain the different places of the pitots between A+B, can this have an influence of the reliability (ice)
I have little (approximately nil) knowledge of AB pitot statics and only those Boeings which I have flown. Generically, I suspect that you will find both marques are similar with multiple pitots around cockpit FS and statics a little further aft (to stay in a shallow boundary layer region without too much local flow acceleration).
Ice problems are probably a bit too specialised for my general comments to be of much use.