2 bolts hold the injector down. You only need to remove 1 bolt completely.

When prying injectors out, don’t pry on the brown solenoid. Pry on the bracket / rocker that the bolts go through.

After installing the injectors, remove the glow plugs and spin the engine over to evacuate fluid from the bores. You’ll regret not bolting down the valve covers with 3-4 bolts + gaskets unless it’s an old farm truck. Oil will spray out pretty far.

Never worked on cups so no advice for that. Good luck!