There isn't really an observable difference in the behavior of patterns 1 and 47 apart from the fact that 1 is "a texture" which can be inverted and 47 is a "a color" which cannot. I suppose it's sort of a puzzling appendix from a certain point of view. Pattern 47 cannot be selected to draw with manually in either color or 1-bit mode; the "white" swatch on the toolbars normally selects pattern 0, but in "Transparency Mask" mode the same swatch is pattern 32, while erasing or right-click fills still produce pattern 0.
It is entirely possible to use multiple solid colors in animation sequences. I demonstrate this in the demo clip of the AnimEdit contraption; I'll add a brief note to make this clearer.