I have a rough in case iron pipe coming out of my basement floor about 18". Do I cut this even with the concrete floor? If not how high should it be? Also, what type of toilet flang do I use (PVC)?

Cut the pipe as flush as you can to the floor. The flange is your option. You could go cast iron with oakum and poured hot lead or one of svereal PVC flange options I like the Oatey Twist-N-Set for $18 but true plumbers would prefer to glue or go oakum on their flanges. There is also a cast iron version of Twist-N-Set.