Compacted meaning i do believe
A, The river is constantly changing. I did this last year so I know what the answer is. Fickle means changing frequently or in my term, stubborn. In his point of view, the river has a mind of its own and changes often. Which he described as "fickle." It may be hard for Twain to pilot a steamboat, if the river is constantly changing.
The Byronic Hero resembles bryons himself, cuz he was already called a "larger-than-life hero"
Cloning is banned in about 46 countries and considering that there are about 195 countries in the world, then cloning is accepted in most countries.