Long story short: Use nano

You can easily customize nano to fit your requirements, especially regarding your desired keyboard shortcuts. To do so, have a look at the bind parameter which you can set in your local ~/.nanorc file. Of course, you can also download ready-made config files (see below).

You can bind key combinations modeled on Ctrl+ with a preceding ^ and Alt+ with M- ("Meta"). Unfortunately, there seems to be no way to bind combinations containing the Shift key. The nano defaults to skip wordwise are Ctrl+Space and Meta+Space. And as if that wasn't enough, you can't bind arrow keys neither. But maybe you can live with these drawbacks.

Because take a look at the bright side: As a matter of fact, there is a package on github, mostly containing improved syntax highlighting, but also coming with almost all of your desired keybindings. Install it by calling make, but be aware that your current ~/.nanorc will be overwritten during the process.

I think you should give it a try, even though that Shift+Arrow selecting seems to be one of your highest priorities. In nano, you would use Ctrl+A to initiate selection mode, so you don't even have to keep Shift pushed down all the time! And you can always use the Ctrl+Shift+X etc. shortcuts that your terminal provides. As you might have recognized, I am quite happy with nano, possibly partly due to being a former Windows user.

Edit: Here's a screenshot showing some of the pertinent key bindings in the bottom help bar.

Diakonos also conforms to most of the requirements:

Frustrated by those other console editors? You already know what keys to press in your GUI applications to open, save, copy, cut, paste and undo. Why should your console text editor behave differently? Answer: it shouldn't.

Welcome to Diakonos, the console text editor with a key mapping you practically already know. Easy to use and easy to configure, but potent in the hands of power users.

Debian package exists, I have no information about that requested flavor.

Emacs comes with a CUA bindings mode. Add the line

(cua-mode 1)

to your ~/.emacs.

Joe is a small-to-medium text-mode editor with configurable keybindings. There is a set of CUA bindings (not in the standard distribution, I think, so install them in your home directory).

joe is, IMO, the best of the editors-that-aren't-vi. It's a decent full-featured editor in its own right, rather than a stripped down featureless minimal editor like nano.

Default key-bindings are WordStar-like which have also been used in many other programs over the years, including the editor in the Borland Turbo Pascal & Turbo C IDEs, should be familiar to many users.

I'm too much of a vi user to use it myself, but I frequently recommend it to people who don't like or want to learn a modal editor like vi, with good results.

Here's the description in the debian package:

 Joe, the Joe's Own Editor, has the feel of most PC text editors: the key
 sequences are reminiscent of WordStar and Turbo C editors, but the feature
 set is much larger than of those.  Joe has all of the features a Unix
 user should expect: full use of termcap/terminfo, complete VI-style Unix
 integration, a powerful configuration file, and regular expression search
 system.  It also has six help reference cards which are always available,
 and an intuitive, simple, and well thought-out user interface.
 .
 Joe has a great screen update optimization algorithm, multiple windows
 (through/between which you can scroll) and lacks the confusing notion of
 named buffers.  It has command history, TAB expansion in file selection
 menus, undo and redo functions, (un)indenting and paragraph formatting,
 filtering highlighted blocks through any external Unix command, editing
 a pipe into or out of a command, and block move, copy, delete or filter.
 .
 Through simple QEdit-style configuration files, Joe can be set up to
 emulate editors such as Pico and Emacs, along with a complete imitation
 of WordStar, and a restricted mode version (lets you edit only the files
 specified on the command line).  Joe also has a deferred screen update to
 handle typeahead, and it ensures that deferral is not bypassed by tty
 buffering.  It's usable even at 2400 baud, and it will work on any
 kind of sane terminal.

It is, AFAIK, packaged for all distros, and source is available at http://joe-editor.sourceforge.net/ - the debianised source should compile on Raspian if there isn't already a binary package.

Try the FTE Text Editor. There are multiple versions available; the one you want is probably sfte which is in Debian's fte-terminal package.