How to force every frame to have a keyframe?

You could "alt + click" on each property to create an expression and press enter to set the expression to it's default. Then go to Animation -> Keyframe Assistant -> Convert Expression to Keyframes and that would generate an keyframe for every frame of your composition.

Johnny Cuevas, Editor
Thinkck.com

"I have not failed 700 times. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work."
---THOMAS EDISON on inventing the light bulb.

Johnny's trick will certainly work for you, but it has a downside. What if you want to change the animated property? If it's in motion, what if you need to change the motion path?

This isn't just a worst-case scenario. I have five whole American dollars that say EVERY professional AE practitioner has had a Homer Simpson "Doh!" moment at one time or another. It typically happens after a file has rendered out, and you're looking at the final result. If it hasn't happened to you, it will. And undoing a boatload of keyframes is the last thing on your mind.

Instead of making all those keyframes, I would instead get to know how the Bezier handles work on the motion paths, and how the Graph Editor works. Then you can animate with a minimum of keyframes.

Dave LaRonde
Sr. Promotion Producer
KCRG-TV (ABC) Cedar Rapids, IA