Flexraid is quite easy to setup as they have built in a "one touch setup" for combined drive pooling and RAID this then leaves you with just having to setup your shares, whilst there are many things you can do with Flexraid for a simple setup as you propose it is very easy to do. there are a couple of tutorials on the Flexraid forum that make it quite painless, I will find you some links later to look at.
WHS 2011 is quite locked down as standard and I dont use an anti virus
Will dig out a link to the custom BIOS for you later.