Im wondering if electrons in rectilinear uniform motion will 'feel' an external magnetic field....?
Yes, they will, but once they enter a region of non-zero magnetic field, they will no longer be in rectilinear motion. Their path is curved.
Yes they will.
This is the reason why image gets distorted when you bring a magnet close to one of those "old" tube-televisions. Electrons hit the screen in order to produce the collors you see. They're in a (approximately) uniform rectilinear motion (they really aren't, since there's always some energy lost when accelerating charges). When you bring a magnet close to it, the electrons are deviated from original path, and you will see some distortion in the image.
I don't recommend you try this at home if you still want to use the television after the experiment (I've done this a few times as a child, and once I did it in the computer screen - WOW, it was really fun. Pity it left a permanent damage in the screen, and my parents didn't share the same artistic tastes as me). I've seen this experiment in one of Walter Lewin's lectures in MIT's OCW, but I'm sure you may find it in Youtube as well.
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