Fighter just means "a vehicle that kills others of its own classification", not a jet.
That is to say, an
anti-tank tank which sounds as silly as an "anti aircraft aircraft". A tank-fighter. It fights, seeks and destroys
other tanks.
As for active defence, a lot of weapons don't work based on where the tank is with a constant feed of information but simulate where its going to be based on its known trajectory and inertia. They compute the statistical likelihood's of where its going to be based on where the driver is likely going to put the tank based on their actions seen prior to the event and how quickly they respond and in turn, usually aim for a volume area the tank takes in most of the simulations, meaning if there are 512 simulations and out of 300 of them, the tank swerves right and puts on the gas at slightly different angles, it'll work out the position they all had in common before the maximum divergence and aim to strike that location.
There's also independent Lock-On-After-Launch, networked guidance, vantage locking (assuming a high position before guiding down onto a target, which is discovered to be especially effective against two-axis CIWS systems because they hit mechanical
Euler gimbal lock and the software takes longer to compensate (its one of the biggest unsolved issues in robotics because of the unpredictable motion it creates -- a common workaround being inverse kinematic systems) and there's silent boresight launching: Launching as a mortar or tank round, then once an altitude has been achieved, guiding down onto a target thrustlessly (making it a bitch to detect).
All of these things give a tank less time to react.
All I wanted to suggest on that front was a CIWS system, even if its only a light one.
As for my massive divergence from your original post, that's the sort of game I play. I like showing there are alternatives. Sort of like the role of a commander on a starship: I don't want to interfere with your vision, I just want to point out potential alternatives and voice any concerns. What you do with your submission is entirely your own prerogative.
I'm showing you potential problems you haven't solved yet because honestly, that's where I get my jollies. My rants are cathartic if useless.
That said, its a very handsome tank, isn't it?