[EC900]

I’d say as many, the 915 is unlike any other transmission. It takes a bit of getting used to and don’t expect to slam shift or force it to gear, let the sychros do their thing especially 1-2nd up or downshift when coming to a stop. There’s a trick to do this like double clutch method or nudging the shifter towards 2nd before going back into 1st. It’s definitely something you get used to after awhile of experience.
On how loose? Gotta pull the shifter and check.
There’s going to be some degree wobble in the shifter it never is tight like other manuals.
The slop you’re experiencing happens when the shifter rod nylon bushing wear or completely broken, the socket cup bushing as well, then the shift coupler in back. The subtle wearing out can affect shifting ease into gear. Once bushing are replaced (easy) the shifting improves and may not even need a couple adjustment. Hardest part is extra time to remove the shifter console if you have one.
So Search topics on that as well as Shifting the 915.

On the stopping on coasting issue, could be binding caliper(s) sometimes happens when sitting too long. I had this on a VW, pads were worn and pistons wouldn’t retract.
Raise the car and check how freely the tires rotate, maybe e-brake needs adjustment or you could try use an infrared heat thermometer to check temps variances of the rotors if one is sticking.

If you haven’t yet, buy the 101 Projects For Your 911 from Pelican. Very informative and complements the Bentley manual.