Thinking about getting fiberglass doors for my '65 Dart. Anything to be aware of with the install? I'm also thinking about doing the '68 Hemi window slide mechanism. Anything I need to know about that with the FG doors?

Most fiberglass door are designed for fixed side windows and have a flange at the top of the door to mount the glass to. If you want windows that go up n down you will have to modify the door top.

What's the set up for hinges and door latch/striker?

Been very happy with RJ Stuff

Hinge kit
https://quartermax.com/pro-series-door-hinge-kit/

Striker kit
https://quartermax.com/door-latch-kit/

Safety strap
https://quartermax.com/door-straps/

although heavy. I used stock hinges. Took the springs off and prob trimmed almost 1 lb or more off each of them. My doors are not lift off, I still have stock front fenders. They do drop a LOT of weight off an A body.