Can squirrels see blaze orange, probably not the color but a bright white object like it comes out in black and white pictures.
You forgot to mention that sneaking up on them doesn't work unless you take a shower first.Squirrels do have an amazing sense of smell though. They can smell a year old acorn through dirt and snow and know by that faint whiff whether it is still good / worth digging up!
Their sight is just horrid though. They can't see me unless I'm moving. I sneak up on them all the time, lol.