For the first:
Person I is slightly polyamorous.
Person II is moderately polyamorous.
Person III is extremely polyamorous.
I'd say all persons I to III can love multiple persons at the same time. Person I's preference is a polyamorous relationship, but they can adjust to monogamy if they have the motivation to. Person II is more likely to not want to have a monogamous relationship. Person III would not be satisfied or could not see themselves in a monogamous relationship.
I'll skip right to the last. I have sort of a kinsey-type scale in my head, where people roughly fall on. More polyamorous is, I'd say, a stronger preference for a polyamorous relationship setting.
I found it a fun exercise, thought experiment. I'll read what others have answered, now.
Last edited by rory; 04-23-2012 at 04:59 PM.