And another happy convert.
The hatches, well, I am not aware of any way you can control the gunner's hatch.
In several tanks, the gunner can open and close the sight shields, however, which is recommendable when you take artillery fire or small arms fire - even a light machine gun can damage your thermal sight or EMES or optics if it hits the right spot too often.
The TC can manually control his hatch, and should use it in deed. For example a shelling by HE artillery with just one gun tube (sometimes a battery with one gun only is used to mimic light mortars) that would not dasmage a heavy tank with closed hatches, can score a lucky hit and kill the TC or even the entire tank when the hatch is open. The AI is suboptimal in handling it, and it takes control of thr hatch and opens it when you jump to the TC's seat and the nb ack to the TC - in this case, close it again. The AI only closes it if it is aware of enemies that cna harm the tank, or an arty barrage has started. That is a porblme since in the Leo2A6 the hatch is different to the others, it is better protected, but takes around 15 or 20 seconds to close due to the hydraulic (?) mechanism.
No known mods for hatches. All skins necessarily follow the 3D wireframe model of the vehicles.