I'm always finding spiders on my outdoor plant. The yellow spider you are describing sounds like a goldenrod spider....I'll see if I can find a picture. I've found them small like you described and about as big as a quarter.umm i dont think there is any webbing and i dont see any other tiny bugs. the spiders are yellowish and whiteish they are really small(about the size of pencil eraser counting the legs)
I think youll find that the second spider is a jumping spider,very small and they jump onto their prey and move well fast,they is good at killing gnatsI'm always finding spiders on my outdoor plant. The yellow spider you are describing sounds like a goldenrod spider....I'll see if I can find a picture. I've found them small like you described and about as big as a quarter.
Personally, I leave them....spiders eat other bugs, not plants.
This is a goldenrod spider...
This guy has yet to be identified...