From the Wiki...
"Cumulus provides some support for extra sensors that can be connected to Oregon Scientific (e.g. WMR-928) and Davis (e.g.Vantage Pro 2 wireless models can have extra sensors whose readings can be interrogated via the Davis DLL) weather stations."
As for running two pgms simultaneously, it depends. You will need a certain set of SW/HW/firmware and an outside program that allows the USB ports to be read. Why make this difficult? Oh yeah, the Davis Extra sensors report doesn't keep the historical numbers.