After splashing around in Mapbox Studio some more and encountering browser woes, I discovered Safari was the answer to resuscitating my missing SVG patterns. I was able to take a pass at turning the hillside countours from tones into dense hatches.
The read is just as strong but it has more of an atmosphere to it with linework. I can't seem to avoid that secondary tiling effect that is a result of non-pixel-perfect SVG editing.
Here are some more of my favorite shots with this map style.