Hmm. Although the baseplate you'd like to use (EZ style, part 524426-1) does have twist-in brackets, it also pokes through above the "bumper." The one recommended for your model Edge (XL style, part 4408-1) pokes through below the bumper. So, the appearance advantage seems to go to the XL.
A call to Roadmaster should confirm if your idea is possible.
2008 Holiday Rambler Admiral 30PDD (Ford F-53 chassis)
2009 Honda Fit Sport