>>Anyway, why keep the vestigial bones? Seems kind of like an inefficient approach to cursing.<<
Nothing is "kept" or a "remnant." It is all there as part of the program in the dna.
It is the same reason the frame of a Kenworth typically has holes that are not used. Several models use slightly different mounting points for different things, not to mention accessories. It is more effecient to just drill the holes in all the frames at once than to have a seperate jig for every style, or, worse, have a workman come by later and manually measure and drill every hole.
God's creation is nothing if not efficient. The concept of growing such an incredibly diverse array of biological machines, generation after generation, with all the instructions for a replacement stamped in EVERY SINGLE CELL of EVERY INDIVIDUAL UNIT is a true engineering marvel.
Thats applicable to a human workman who has limited time and effort available. But your God is supposed to be omnipotent. Why does an omnipotent deity need to take short-cuts? If you can say 'let there be light' and bam!, there is, why can't you say 'let there be snake' without putzing around with lizard designs?