Nasty Z gave a link to adapter that would work, it is designed to be added to trans pan but has right specs to go in your oil drain hole.
http://www.summitracing.com/parts/BMM-80250/?rtype=10

Might be a cheaper brass fitting available?

Using stock CTS sensor is easy start, cheap part even if new. Not sure if it would work tied to ECM and a gauge... Probably not as the stock EFI system has seperate sender for gauge and ECM.

Not sure on rest..