I have a totally unsubstantiated and unscientifically tested idea that a higher percentage of poly women tend to be Pagan than is true of the average US population.
And I did have one date with a Wiccan polyamorist but we turned out to be a rather bad personality fit. (There was a lot of slapstick and talking at cross-purposes. In retrospect it was very, very funny...at the time, not so much!)
I suppose the prime consideration for someone entering a poly relationship is whether they are able to avoid wanting to possess a partner. That seems obvious, but if one has a tendency to fall in head-over-heels in love and want to be with the other person every second of the day then poly may be a struggle. I think that it takes a certain mindset to say, "It's time for you to go back to her, because you need her and she needs you. I'll phone you tomorrow and maybe we can see each other again in a few days" -- to say that to someone you love dearly, and feel good about it.
You've come to a good place to ask questions -- I'm a newbie, but many of the people here are exceptionally wise and very, very open. Welcome!