Pressure testing at the head shop will reveal any cracks in the head, which might or might not be weldable. I'd bet against cracks.

The hydro lock issue could be big--you might have been "lucky" and just blew the head gasket in the process, hence the lack of other obvious damage.

With regard to the bent rod possibility, you'll need to measure each piston at top and bottom dead center. the edge of the crown of the piston will stick about a 1mm or so above the top of the head at TDC--if there is any variation between pistons, a bent rod could be in your future. . .

Far as the oil, with the injector down the center of the valve cover, anything in the injector bore is going in the cylinder when the injector is removed. As you turn the engine over to check the piston heights I'd be more concerned if you ended up with lots of oil on the cylinder walls. . .

G