Can I connect 3 screens to my iMac?
From the link I can only find the interface used is DisplayPort (not Mini Display Port or DVI) which to my knowledge are different standards which means item 1) would not work

For item 2) what is the purpose of having multiple displays? Are you repurposing extra displays or actually have an alternate need?

For item 3) I use a USB display monitor which allows me to connect multiple additional screens trough different USB ports in addition to my standard display out.