All seems normal with your machine.
But I will say on the "lever returns to neutral" thing:
Mine never goes to neutral after dropping anything, but it always went to neutral after raising things UNTIL I mis-treated my 3PH after augering my PHD into the ground...I held the lever "up" while at full throttle, rocking the tractor back and forth trying to recover my auger.
After that mishap, I noticed it would NOT return to neutral. I also noticed a bit more "whine" out of my hydraulics in any movement, even the FEL.
I had my machine serviced shortly thereafter and had all fluids changed. Everything is back to normal, no noise (more than original, anyway), and the lever goes to neutral after raising. Dealer figured I stressed or overheated the system and induced a leak out of one of the quick connects at the FEL or BH. Not sure if I buy it, but a complete hydraulic fluid change did the trick.
And the FEL and 3PH DOES work at idle, it is just slower than Aunt Edna. Almost too slow to even know anything is happening. Idle is idle...not good for much other engaging the mower deck and moving really slow around the garage. Everything else requires at least 1/4 to 1/2 throttle, depending. Real work requires 1/2 to 3/4 throttle, depending...this is where almost all your FEL work happens. Mowing and super-duty work (full FEL capacity, full BH capacity, full ground speed, and ALL mowing duties) happens at WOT.