Honest answers to your post install roofing questions can be hard to get unless you hire a trusted local roofer. Honesty in the construction industry can be allusive unless you check your roofing company out with the Better Business Bureau and online first.
Do not worry about your new shingles not laying flat they just have not thermal sealed yet. The Owens Corning Tru Def Duration shingles are the shingle I recommend. One reason I like the Duration shingle is if your roofing in summer or winter they come out of the bag nice and flat. Another good function of the Owens Corning single is they thermal seal very fast, much faster than other brands of shingles. The hip & ridge shingles are the same way, they must be given time to thermal seal. I prefer the Owens Corning DuraRidge for your new roof project. The Owens Corning DuraRidge is made for your homes hip & ridge and is shaped for the bend they will have. A three tab shingle is made to lay flat and is not engineered to bend and is not a good choice for a hip & ridge shingle. Your roofer or roofing company crew manager should show you pictures of rotten decking to reassure you that they did not nail into rotten decking. A good and trusted local roofing company in your Hammond or Baton Rouge city should take the old felt off your roofs deck and remove all old nails from your deck. If they don’t ask them why not, I call it lazy roofing and you should find a good roofing company to replace them. It is very common to have post install roofing questions when you see something shinning at the top of your home. The ridge vent on your home has a flat side facing downwards but still angled at the sun just enough to be real shinny when the sun hits it just right. Nothing to worry about here, the sun has to be just right and it is just a reflection downwards. Owens Corning has a new version of their VentSure ridge vent that does not do this nearly as bad as other products.
In closing if you have hired a roofing contractor from your Baton Rouge or Hammond area and they are trusted in the area let them do their job. Please have a list of questions for them but always before you start your new roofing project is the best time to weed out a roofer you should not be using.