I don't think it's cut and dry like the original you quoted BUT they could have decided to use the design as marketing.
1. Go with genuine vision of sonic
2. Leaks of poster get a lot (relative for sonic) of internet commentary
3. Trailer is presumably the first thing that's been fully rendered and they decide to show it to get a bigger reaction
4. Shortly after 2, they also start planning how the CG can be redone in the main film and basically get a new model up and running
5. Trailer shown, lots of mindshare achieved, and promises can be made of a rapid fix.
Is it likely? No idea, but it's certainly plausible.
If you're deep in production, the poster leaks, and it looks like people will be "horrified" by the design, then the events that have happened are the least worst way out of that hole...if not the most honest!