Sounds to me like you're doing this thing in a smart/sensible fashion, and that you're off to a good start with your V companions. The only fly in the ointment is that you may be second-guessing yourself, e.g., "Was I really supposed to do that in that way?" It's all new right now, so I'm sure it's gonna feel weird for awhile. Just be patient with yourself, and with the process. Inevitably, difficulties will crop up. But you can't predict those. They tend to be different for each relationship.
I think you'll do fine, just keep taking those deep breaths, reading, studying, whatever helps you start to get your "sea legs" on this poly boat.
Sounds like the metamour's a pretty cool person (as are the two fellas in the cast of characters). Congrats on one big milestone, on the books.
Love means never having to say, "Put down that meat cleaver!"