So I frogged the border back to where I'd made the mistake and reknit with the sport weight yarn. Then I did the first sleeve. The sleeves and body will be joined at the yoke and worked together from that point. I am working now on the second sleeve. I did get the fingering weight yarn, which I may use in the next pattern part, but for now I like how this yarn is turning out and don't want to change anything yet. I'll have to experiment with both yarns to see which works better for the next part.
Here's what I have this morning. I'm rather pleased that the two sleeve hems look so similar. I don't always get the sleeves matching. (Note to other knitters: No one ever notices these things if you don't point them out.)
And now I am going to go paint my hallway.