1. I found information from Ju87-D1 Handbook about elevator trim left and right was separate operation.
Left elevator trim was operate by elevator trim wheel on the left hand side of cockpit and in IL2 BOS is operate correctly.
but for right elevator trim was operate by hydraulic oil correspond with dive brake description as per below.
I've translate operation description by google as per below.
Compression system dive system
In the "brakes" position, the two dive brake flaps are located on the underside of the wings (the pistons are driven out), the two right-hand trim elevator flaps are turned on (piston of the working cylinder moves to the left;
When triggering the bomb button the trim tabs are retracted again (intercepting device part 4 "control unit").
Only when the dive brake lever is moved to "retract" do the dive brake dampers enter, and the piston of the working cylinder HC16 is adjusted according to the direction of the tail.
If the bomb button has not been actuated, the trim tabs can be adjusted by retracting the dive brake flaps.
In this case, the working cylinder of the height trim trimmers is pressurized at the same time as the left dive brake damper of connection 7 of the sliding switch (HC3).
but in IL2 BOS have no any action when dive brake extend.
2. Does water cooling armor (Panzerplatte) was modeled?
Reference : Ju87 D-1 trop Flugzeug-handbuch Teil 4 Steuerwerk, Teil 5 Tragwerk and Teil 9C Druckölanlage