Here is a closeup of the tube I replaced and it sounds like you got the part for. I added another circle for where the tube attaches to the filler. I'm not on expert on how much oil is in the tube while the engine is moving but it must spray up there to have leaked at both joints on mine. There would not be oil in there while the car is not running.
If the leak came from the joint on top of the engine it should be obvious...just look for a puddle on the engine under the joint or feel for oil on the bottom side of the joint clamp. If your leak came from this joint it should be obvious considering how much oil you say was on the ground, to create that much spilling oil the engine would be a mess under this join.
To see if the leak is coming from where the tube attaches to the filler you'll be able to see it with a flashlight looking up from under the car, there are a lot of things in the way but you'll find it. You could also reach under from the top and see if your hand is covered with fresh oil.
Based on the things you just replaced you'll be able to replace this tube too. It is not fun but with right tools can be done. Obviously the end that connects to the filler is the hardest. Look at it closely from underside so you have an idea what to feel for when you reach in there to open the clamp, you'll need something that can hold the clamp open while you work it loose. You might need a mirror to see well from the top. I used regular hose clamps when I put my new one back in. I had the transmission out while doing mine so I could do it from the underside a little more easily. Not going to lie to you, this was not fun. Let's see if others have some good ideas, my way might have just been beginner bad luck.
As for what the pipe does from the middle of the engine on I'm not sure. You could remove the air intakes and look.
