Your hood is probably fine, it's the header panel that needs adjustment. There is a bracket that goes from the center of the header panel to the center of the core support. It's kind of a flimsy bracket, and is usually the cause for the sag in the middle of the header. Especially if people have leaned on it. Just be glad it didn't break instead. Be careful if you try and adjust it, as the SMC that the header panels are made of doesn't really like to be disturbed, and you may end up stripping the mounting holes. Try and get your adjustment out of the upper and lower mounting points on the core support first.
For your trunk, try putting some shims in the two rear most bolt holes. Four bolts hold the lid in place. Mark your hinge locations with some tape or something first, so you don't lose your original positioning. Then loosen the rearward most bolts. Then slightly loosen the inward most bolts, the ones closest to the rear window. This should give you enough play to put a couple shims in between the hinge and the trunk lid.
The best thing you can do to be able to best utilize the adjustments provided, is to really get familiar with how everything attaches. From there, figuring out where it can go becomes much simpler.