Will there be a flashfire mount to replace the turret with an appropriate sized fixed mount? / Are we able to change out the top turret for one large fixed gun?

The flashfire mount design is being revisited. The Hurricane's turret was designed to fall in line with the newer turret/remote gimbal system. The current direction is to limit the allowed size increase / mount cost to prevent too much edge-case exploitability; where a S6 would be overkill, 2xS4 might be ok. Furthermore, remote gimbals may have stricter resource bandwidth than turrets, so the peak installed performance of such guns may be less than if they were placed on a standard fixed mount, but again, this system is in the middle of revision, so please understand that this is very much subject to change.