my 9800GT idles at 68 and gets to 90+ degrees under load and I've yet to experience any "damage". 70(c) is not an unexpected idle GPU temp.
SLI probably isn't going to work unless the chipset drivers are installed, considering that for hte most part SLI/Crossfire are motherboard features as much as they are graphics card features.
Additionally, SLI is unnecessary to have two cards installed and recognized. They should show up in the Display Settings page. (Control Panel->Display Settings)