Changed tcase oil, level was about right. T case looks very clean and solid, leak likely not from that.
The photos are of the transmission, just north (towards the front of the car) of the plastic transmission pan. That's either transmission oil or engine oil, I'm guessing. Has to be slow leak, as there's no pooling anywhere.
I'm planning on changing zf oil, though I wasn't going to change filter (due to issues with dropping pan/access/and various recommendation says not needed) just drain as much as possible, and do multiple drain& refill to change out most of the oil. Wondering if I should try to drop pan in case that's where leak is. Although, leak when car is moving, would cause oil to go further back, and not move forward - this is grease in the forward direction from pan.
I'll also inspect engine bay area (remove some plastic), to see if I can see the source.