Alt + click while in brush mode doesn't change to eyedropper. Also eyedropper tool selects color for paint bucket tool not for brush. This is quite tedious and would like to fix this issue.
Alt-click while on the brush tool is something that does work in Photoshop. I don't think it ever worked that way in Animate, though it seems like a good idea.
There are two paint brushes. The one called Paint Brush Tool draws strokes, and so uses the stroke color. The other one is Brush Tool, and that paints with the same fill color that the paint bucket uses.