No - the full version of the rules (rather than the "marketing version" on OneWorld site) are clear that you may only have 4 segments in Europe (and you may not purchase extra segments in your continent of origin) so you need to lose one of those segments. http://www.hardlink.com/~markdu/OWFi...eExplorer.html

Qs 3, 4 & 5: yes all OneWorldExplorer flights in business or first get status on AA and qualify for the challenges and get lounge access.

Q6 - I don't think it is possible to bargain the ticket price; certainly not for a credit card purchase. Perhaps 1-2% if you offer cash, but I have no direct experience of that.