The plan sounds pretty good. I will be wearing something similar myself, although I'll be going with a Haspel seersucker suit and a SoPro bow.
As far as the criticisms go, I think people are forgetting regional variations in style. While the outfit might be inappropriate up in New Haven, it's perfect for down here. A great tie with shotguns would be a fun piece on any day, even Easter, down South.
A dark suit would be more formal, but unless you attend an Episcopal Cathedral, you'd probably be out of place. Easter is a great day for pastels and fun Spring/Summer fabrics.
I would avoid the Sperrys unless you're still in school. Of course, this all depends of your church. Even in Sperrys you might be the best dressed guy in the Parish depending on your congregation's style.