I think your downlock explanation is absolutelly right. Downlock strut is overcentered only few degrees, so it is not clearly visible, but neccessary for transfer structural load. Stops for overcentered position are visible in mid lower part of image. Hydraulic pressue for down(lock) side of actuator is present all the time if B pump(s) runnnig, L/G lever in DOWN and access door for free fall extension closed. Spring main task is provide positive locking (overcentering) in case of free fall extension.
And sorry for too late answer
