I'm not 100% sure on all of them, but I can try:
Scroll delay: the speed at which you can scroll
Scroll step: number (of pixels?) you scroll each "step"
Text delay: how long "floating text" will appear on NPCs. I think this is in addition to some default time.
Cache sprites: Presumably how many sprites are stored in cache memory while you play. Increasing it will require more RAM, but speed up subsequent loading times.
Texture size: Size (in kb?) of textures stored in cache. Same thing as with cache sprites, if you increase it, it might speed up loading times, but it will also require more RAM.
3D FPS/3D smooth transition: This has to do with 3d models which aren't used in AoP.
Damage indication on head: when something takes damage, it will appear as red text over the head. The number is how long that text will appear.