What does the tire look like? Is it oddly wearing? Cupped? Out of balance? Pressure? This vibe is exacerbated by speed and always present or absent and then presents when a speed is reached? To be clear this is an oscillation type vibe? You said you cleaned the calipers...what did the pads look like? And the rotors? Pad and rotor wear uniform? Forks at uniform height in trees? Forks adjustments uniform from one to the other? I would not think stiction/springs would cause such a vibe. I would think that something rotating was out of whack. Something warped , unevenly worn, not balanced, etc...
Just throwing some stuff out there. I don't claim to have great experience with this type of stuff...hopefully someone who has had and remedied this type of issue can chime in.
Tyre looks ok, had a few bobbles the other day from some sprinted riding, i removed those and felt very little difference.
tyre is wearing evenly, pressures are good, and it doesn't feel out of balance.
speed has no affect, its there from 0-70mph after that its hard to tell.
pads and rotors are good, brakes seem to bind less now, wheel spin's three or four times without stopping, previously it was half a turn (spins and spins and spins with no calipers on so bearing's are good, with no side to side play)
forks are the correct height and uniform.
forks have been adjusted and set correctly.
Its not an oscillation type of vibe, only happens when going over undulations in the road or cracks, id almost say its on the rebound stroke that it vibes.
Just a bit about my background, i used to work for ohlins, and trained as a race mechanic, i currently work as a development engineer designing parts for F1 amongst other things , and this still has me completely baffled lol
I've just rebuild the front of the bike from bare frame up, i did find a few lose body panels and possibly some missing nuts (see above) but nothing out of the ordinary, lets hope it was something silly and its been sorted by the rebuild.