I use Ctrl - Alt - i to move the cursor to up window, actually I use ijkl to move cursor to different window in four directions.
When I enabled flyspell-mode, the Ctrl - Alt - i is overwritten. It was used to correct misspelled words, but I never use it.
Maybe you accumulated too many unstaged changes, maybe there are man different changes gathered in a same hunk. No you get a hunk contains totally different code, you may not want to stage them as a whole. If you are in command line, you can use git add -p. But this feature is very limited, you just can not .
One of the things I miss about VIM in Emacs is :%s command, which allows you input pattern and replace text in one step. The Emacs M-x query-replace-regexp do the same thing but a bit annoying, you need to input regular expression first then press enter, input replace text and press enter again and you need to press ! .