Ken, I take off any leaves that start to look yellow. If they rot instead of drying up, they could harbor fungal infection. People who show their orchids take off every leaf with the slightest imperfection, and it doesn't hurt the plant one bit, so I figure they probably know best.
As for the terminology, stem, spike, stalk, sheath . . . let alone floof and doodaflatchies. It's all Orchidese to me.
If you had the Phals outside after the nights cooled off, then brought them into the greenhouse, they may think it's spring, and that's why they're spiking already. Last year, we had just a few cold nights, and I brought my Phals into the house. Every one of them had a new spike within 2 weeks of the cold-to-warm experience.