Rotational noise from rear

[bekks]

2000 S 6 speed manual. 90k km
I have a noise that is coming from the rear that increases in frequency with the speed of the vehicle, but not the engine. It definitely coincides with the rotation of the wheel. Coasting to a stop seems to make it the most audible, due to the lack of engine noise. Sounds a little bit like a rubbing/grinding noise, but not like a wheel bearing and it is not discernible over 60 km/h due to road noise, although it maybe seems to diminish when cornering.
I have put the car on jack stands and ran it in gear and I can't seem to replicate the sound, I've also jacked up the wheel I suspect (right), while on jack stands, but that didn't make a difference. While investigating under the car with the wheels turning, I noticed the transmission is making a little grumbling noise, but I don't think I can hear this from in the car and the transmission makes the noise whether it is in gear or not (still need to check if it does it with the clutch disengaged).
I took the brake disc off one wheel cause it was making a little bit of a grinding noise spinning by hand. Nothing significant came out, but it was quiet when spinning by hand afterwards (that did not fix the noise I still have though).
And one other thing of note, I was on a nice twisty road 2000 km ago and came around a right hander followed by a screeching sound from the rear (I thought the car was done for), but as I coasted up another 50 m to pull over the screeching went away. Couldn't find the cause, but I think that may have been the start of the noise I am now hearing.
I realize it's tough to diagnose a sound through a forum, but I can't figure it out.