1. You can also just configure Git to use whatever editor you'd like.
https://git-scm.com/docs/git-config#Documentation/git-config...
2. You don't need to be a Vim pro to interactive rebase effectively. Most of it will be `dd` to remove a line, `p` to paste a line, `j`/`k` to move up and down lines, and `cw` to change `pick` to `edit`, etc. Spend 15m with `vimtutor` (which is probably available on your system) and you'll never be afraid of vim again.