When you change the serial number on the second node, be sure to change it to one of the serial numbers listed in one of the 8.2.x simulator license files.
Multiple simulators are absolutely possible, you just have to use serial numbers with published license key sets. There are at least 9 sets available, more if you've been paying attention to the RCs. You can use serials/keys from both the 7mode and Cmode list. The feature keys are node-locked to a serial number. They aren't really 7mode/Cmode specific, except for the cluster base key which doesn't apply to 7mode anyway.