There's quite a fewout there, might look at the Asus X99-A, the X99-Strix (which is what I got and love it (in sig)), or up a little more to the X99-Deluxe II
Total security is an individual product - Family pack includes Total Security and also adds AV for MACs and their mobile security - so the family pack allows for 5 users and as many devices as they want
Yep very few games, with only 4GB of DRAM the integrated graphics is going to take a decent chunk of DRAM as will the OS and any programs that load in start up leaving you very little for gaming. Most games these days call for 8GB in the system