I think you need to find out why the signal is at zero grams a sec. The motor will still run with a dirty MAF. It could be covered with oil and dirt and still run. The signal is dropping out and that's were you should be focusing your energy. Clean or dirty. it should have a signal

Well it comes down to what "visually" you can live with. The new damage is in a area that has been previously repaired and not the original surfaces. Yes you should seal the damage as water will probably cause further issues. The yellow in the pic's is going to be a filler that might not b...