Does the Downloads folder always exist

In this case, open -a is NOT what you want; the -a option is for launching known applications (indexed in the Launch Services database that lets you open a document and get the right application) by name, not by pathname, or for opening files with a given application.

What you are looking for is just plain opening foo.app, just like you double-clicked it in the Finder. To do that,

open foo.app

This will open exactly that application, without involving the Launch Services database at all.

Finder does not have a bar like in the explorer on Windows, but there are some things you can do to achieve similar results.

To have the current path always visible, open a window and go to View > Show Path Bar. This will add a bar to the bottom of your windows which shows the path of the selected file, the same as if you were in search view. You can also Command-Click on the icon at the top of the window to view the path as a menu. As noted by @lhf, copying a file will also copy its path. You can also drag a file from the window or path bar to most places where a file or path is expected, such as open or save dialogs.

To go to a folder based on its path, press Command+Shift+G. This will pop up a box where you can type in a path, and either the current or a new window will open at that path. This also works in open and save dialogs.