I can't help you with ABS as I have never owned an ABS-equipped e30. (I presume you are asking about an e30 this time as e21's didn't get ABS)
The shifter slop is due to worn bushes in the shift mechanism. There is a knuckle joint with a bush where the shifter attaches to the tranny, and another on the end of the shift stick. Then depending on what year vehicle you have there are other bushes where the console that supports the mechanism attaches to the tranny.
You don't have to remove the tranny to replace them. but you will have to remove the prop shaft and drop the tranny mounts a couple of inches to gain access. Even then its a simple, but fiddly job.
Look here (This is for an e21, but early e30 is exactly the same)