Can't share specifics to all your questions, but I did want to make a couple of notes:

-If you merely "prefer" automatic but "can" drive a manual if needed, you should strongly consider driving a manual. An automatic will be significantly more expensive.

-A US-issued DL is generally sufficient in most other Western countries, though it never hurts to stop by your local AAA and pick up an international driving permit just in case you run into that one agent at that one agency in that one city who decides to enforce some obscure policy to require one.

-There is no such thing as a "normal" rental cost. I'm in Alaska now. Three and a half weeks ago, a friend picked up a rental car here for $3 per day. Last night, I looked for a car here for someone else and couldn't find anything less than $150 per day. Plug in your dates and see what comes back.