Hasrat, the one-swing skills do stack with the all-swing skills. I was using King’s Yield 2 on the new ore last night, and Pick Clean, for 4/swing. Once my GP rose back above 100 using Bountiful Yield would see the next swing garner 5.

As for gathering ‘garbage’ ... you should be able to avoid that now. Item tooltips have the words Crafting Material on them when they are used in a crafting recipe - with the possible exception of gear, that is; I’m not sure if the low level gear that is used to make a stronger piece of gear has that term on it. But seeing as gear is not something you mine or harvest anyway ...