Not that your explaination wasn't a little confusing, I think I follow you. And that's how classic tweens work.
Modern tweens add keyframes for an objects 'properties'. Things you find in the properties panel amongst other things. Classic Tweens do not. They operate on animating basic transform-esque properties (or shape morphing for graphics). Some of the properties you desire to be tweened probably aren't part of what a Classic Tween supports.
Classic Tweens came in 2 varieties as well. One was a graphic tween that would morph whatever was on that layer between keyframes (if it was possible or practical). Perhaps that is what you want for something like mouth movement.
Thanks for your reply. Sorry for any confusion. It's often hard to relate things in text that would be really easy to demonstrate in person. Do you know if there is a way to separate two classic tween sections that are next to one another on the same layer? Part of the problem is that when I apply classic tweens between keyframes, they all blend into a single tween-span. If there was a way to have distinct tween-spans that were neighbours, then maybe I could achieve what I'm going for.
This is an example of what I mean. On the left is part of an animation someone else did. You can see that there is a classic tween in place, but there is a line separating the final keyframe from the rest of the tween, and I can adjust the properties of that keyframe. I can't figure out how to achieve that separation, though. On the right is what happens when I set up classic tweens; they blend into a single span. As you can see, there's no line in place in the middle keyframe separating it from the previous segment.
Just in case anyone comes across this and has the same issue, I figured out the problem. In the properties panel under Tweening (which is active when you have a tween selected) there is a box checked by default titled 'Sync'. Unchecking that will allow you to create discrete tween spans side-by-side.