You don't need to look past the D5000.

All DSLR cameras have plenty of manual controls.
But while you are learning about how to use them you can always put the camera in Auto and fire away.

Panorama: Panorama is just a series of shots that are stitched together with software. Any camera can do that.

Sony is touting "sweep panorama" on some of its cameras.
A special setting that will automatically snap shots as you sweep the camera from left to right. Then the camera will stitch them internally with firmware in the camera.
I just wonder how well it stitches.
Most panoramas need some touch up with a program like Photoshop.

You have the right idea on the lenses.
Learn the one you have before thinking about more lenses.

8 megapixels is enough, unless you are planning to print poster size pictures.