Put viewport in solid mode, enable xray on lowpoly in object properties, in the N panel enable Hidden Wire under Shading once you've entered edit mode.
yeah its not great but you can enable vertex snap and face snapping (use shift) with project onto self enabled - then also enable auto merge (top bar to the right -> options, also crank up the merge distance) and it should be somewhat close to what you expect it to do.. but that tool needs some love.
You can just enable 'Emulate Numpad' under the 'Input' in the preferences. Doing this maps the numbers above the letters to do what the numpad keys would otherwise do. Those numbers are otherwise regularly used to switch layers which isn't something used that often anyway (for me at the very least). While you're in there…
All is not lost! Emulate Numpad to the rescue ^^ In 2.4x go to Preferences> System and OpenGL and enable "Emulate Numpad" In 2.5 go to Preferences> Input and enable "Emulate Numpad" It allows you to use the standard number keys in the same way as the numpad. ftw! :D