a high front fender and a fork-mounted fairing can have some influence on riding-stability, especially on fast road-sections. A high-level fender won't get clogged up with mud leading to a locked wheel in worst case. A fork-mounted fairing with head-light can be turned at a standstill to have a look in different directions in the dark. A frame-mounted version can't do that for you ...
The beak ... riding the grandmother of all beaked adventure-bikes, a 1988 Suzuki DR Big 750 I still can't tell you much about it's influence. Maybe, it offers a bit of stream-lining. Up to 100 mph my bike doesn't develop any instability. At that point, it runs out of steam, too ...
Kind regards, Bambi
PS: in the 60- and 70-ies there was a story going round concerning low-mounted front-fenders here in Germany: top-riders would give a hint to their riding-skills that way, as they had to keep their wheels turning all the time. Coming to a halt, you wouldn't get on the move again as the mud would lock the wheel instantly! Herbert Schek for example on his home-built BMWs still is one of these top-riders - aged over 70.
'Find me kindness, find me beauty, find me truth ...'
(Dreamtheater, Learning to live)