Soot & dome discoloration

Hey everyone, first time poster and noob to the BGE life. I've had my XL BGE for a couple months now and everything's been great and smooth. I tried my first attempt at a low and slow rib cook last weekend. I have a couple questions.

Question 1: At the end of the cook after the ribs were done I decided to throw some veggies on the grill. While they cooked I noticed a large amount of soot getting on them. I didn't notice any getting on the ribs but it was hard to tell especially with spraying them. Any thoughts?

Question 2: After cooking everything and the grill had cooled I noticed a discoloration on the inside of the dome between the front half and the back half. The front half of the grill had an almost glossy black shine to it where as the back half had the standard dull black from smoking/cooking. Any idea what could have caused this? I wonder if the soot and this is related?

Things to note: Standard lump charcoal used for the cook, it's charcoal sold at my local BGE dealer so I assume it's good quality (probably my first mistake). About 3 hours in to the 4.5 hour cook my temps were dropping so I had to pull everything out and add charcoal to get it back up (rookie mistake not having enough charcoal in). I also added additional wood chunks since about 2 hours into the cook the 3 chunks I had originally put in stopped smoking. Last, I used a water pan with water in it which had dried up around 2.5 hours into the cook as well.

Sorry for the long winded post but I appreciate any help/advice!!

Thank you!