Quick questions about aligning and snapping

How can I align these vertices which you can see in the picture below? Whenever I try to snap them into same line, they align in all axises but I would like them to snap on only z and y axises. I hope you can see what I mean in the pictures.

Before snapping: http://postimg.org/image/fr1wgry5t/full/
After: http://postimg.org/image/t6ox686nl/full/

Another question I would like to ask is about snap to grid. Is it possible to use it on for example on only z axis like I would like to in the picture below.

http://postimg.org/image/3xdwnsso7/full/
http://postimg.org/image/6fzloheef/full/

And while I am at it, is it possible to customize quad view so that when I switch between it, I would have normal perspective view instead of camera pespective?