Wake on LAN in the BIOS enables the computer to be woken by a specifc 'Wake on LAN' packet. This will not allow the computer to turn on when files are requested.
The best way to determine the answers to your questions is to set time sleep to a shorter time (like one or two minutes) and try each thing. As far as I am aware, a computer sees inactivity as no input by keyboard or mouse - when I am rendering animations for instance, all 8 cores of my i7 are at full load, yet the screen saver will still come on if it is enabled (I turn it off when I render). Usually a computer will sleep regardless of what it is doing (even in the middle of a download or encoding a video).
My advice would be turn off automatic sleep. If you know you're going away from your computer, you can put it into sleep or turn it off. I know this isn't as easy as auto standby, but it solves all your problems doesn't it?