It shouldn't hurt it, it will still burn. Many Semis usually put used motor oil in their gas tanks just to get rid of it as SOP in their motorpools.
I've never seen one with a weedeater, but I have seen one with an edger. That would be nice wouldn't it? How about the Packer-combo-mower ?
The surplus will drop back onto the lawn.
nothing
Your clothes would get cleaner.
it will explode
I barely know.
It depends on the design of the mower. In one it might blow the fuse, in another it might go backwards. Or the blade might go backwards, which would be useless.
There will be no human
The salt would dissolve, which you can reverse by boiling the water.
The ink would mix into the water and become diluted.
it would grow at a faster rate then a normal seed
If Argon gas and Copper metal were mixed together, they would not react chemically because Argon is an inert gas and Copper is a stable metal. They would simply coexist without interacting with each other.