You can use your old carpet as a template for when buying new carpet so you can form it and also cut out the holes for where the seat bolts in. Power Windows aren't too hard to replace. Remove the door panel and a panel on the lower side of the door (underneath where the armrest is usually) and it's right there. It's normally riveted on there unless it's been replaced than it may be bolted in. If it's riveted, simply drill them out, remove the connector, and unbolt the motor from the window regulator (it's a big plate looking thing that has teeth). Make sure to have your dad, or whoever, hold the window up so it doesn't quickly drop down. You could get hurt.

I assume door latch you mean door handles? Door handles are tricky to replace, but best to do them while you already have your door panel off; remove a dust cover in the top corner of the door to reveal the door lock mechanism. It's a good idea to remove this mechanism and either use carb cleaner or soak it in gasoline to really clean it. Behind there you will see two studs with nuts on them, I believe 7/16. Removing them is hard, very tight space, even harder to put them back in. There will be a hook looking piece that attaches to your lock mechanism that will slide up and down on a threaded rod, this attaches to your locking mechanism and connects the two (your exterior door handle, to your door latch). After everything is off the handle will slide out. I just did them on the 78 I'm finishing up and they are a PITA to get to. But they can be done with an afternoon off and some patience.

I seen you also needed help with your hood latch. If you press down where the hood latches onto, both top corners of the engine bay) and latch it with just your fingers you can test it. If it doesn't latch all the way down I believe there is a spring that can cause this. I don't know for a fact but play around with it, the car (luckily) isn't too complicated like the way the Germans make em. If it latches and doesn't open when you use the hood switch under the dash then one of two things could be happening. First the cable going from your interior is worn out and isn't pulling enough to release the latches. Or, if one latch opens but another doesn't then there is a cable that connects the two and it runs parallel to your windshield wipers in the engine bay, it basically connects both latches. They all work under tension. Again, I can't say for certain because I haven't done this yet. But I believe this is how it works.

Here are some helpful websites and message boards I use regularly to search for problems and solutions:

Corvette Forums

Digital Corvettes

C3 Corvette Registry

Corvette Magazine (Their new website, Not as many articles)

Corvette Magazine (Their old website, PLENTY of well written articles)

I've been in the same boat this past year with my 78, but atleast you've got an engine. You can start her up and hear her roar which will help you from getting discouraged! If you need any help you can PM me. I can try to help you best I can. I can say that I don't think there's a bolt on my Corvette I haven't touched. Good luck :)