1/ That's correct. "tint" is basically a multiply blend mode, which is good for that sort of thing.
2/ The best description of what the blend modes do can be found in the "Layer Blending" section of the Manual from the Help menu which describes the 4 basic modes ( Normal, Tint, Shadow, Highlight ). This also has some visual examples which explain them better than I could here. The rest of the blend modes are comparable to Photoshop's blend modes.
3/ You could either use the pencil with "precise" turned on, or the marker tool at a very small setting I would say for the look you're probably after.
4/ There isn't a flood fill tool in ArtRage, but you can use the paint roller for large areas ( pressing lightly lays down thicker paint as it doesn't get squashed down as hard ), and use stencils to constrain yourself to areas.
Hope that helps!