Color legend for a single graphics object

Context: I'm working with a M-by-3 that I've categorized into 4 different groups. As part of the visualization of this data, I'm creating a MechE-style 4 view drawing. The 4 groups are defined by 4 logical masks of length M.

Problem: I would like to have annotation, legend, or similar to explain the color-coding I've applied to 3 of the views in this figure (a scatter, a scatter3, and a third yet-be-be-determined object). So far, the only solutions to this are inelegant at best. My own solution (below) isn't much better.

%minimum code snippet
colormap(AxHandIso,[[1 0 1 0.9290]',[1 1 0 0.6940]',[0 0 0 0.1250]']);
colorbar(AxHandIso,'Ticks',[0.125 0.375 0.625 0.875],'TickLabels',{'What Yellow Means','What Green Means',...
    'What Red Means','What Orange Means'});
ColourLegend = legend(AxHandIso,'EnoughTextToPreventClippingColorBar'); ColourLegend.Visible = 'off';

Question: Is there a better/more elegant way to create an annotation which occupies the same space as a legend in the WestOutside Position, automatically resizes the axes object(s) in a figure to accomodate itself, work within a tiledlayout, and does not involve creating superfluous graphics objects?

Side Question: Why doesn't lcolorbar accept a target argument?