Yes to all of this. Vim can be used as a IDE. Vim is super fast and there are tons of extensions out there. For specific languages and frameworks.
Pretty easy. Type
$ vimtutor
into your shell of choice and make every day a few lessons. It is a tough start, because inside vim you have an own language for controlling vim. However if you master it, you will be faster then with any other editor.
There are some nice tutorials out there. I really like the latest Laracast Course because it will introduce you to a very important part of vim, your .vimrc
Another good one is learning vim in a week
Like mentioned, on of the most important parts of vim is your .vimrc, a few people recommend downloading someone else vimrc because it's "ready to go". I am not a big fan of it.
You should build it up yourself. Step by step. Thats why the laracasts course is pretty nice. But there are a lot of other introduction tutorials which are nice too.
It's important that you build up your own vimrc, because you need to know your key bindings / rebindings etc.
There are ton of plugins out there. You should consider using a plugin manager like Vundle. Some popular plugins are
etc.