Most of the sites you are searching (Traces of War and The National Purple Heart Hall of Honor) rely on supporting documentation to be submitted by family, friends, or public records. In both cases, they are a starting point to verify what has already been submitted, but are in no way complete. For World War II, you would be looking for WD AGO 53-55 and would not to submit a SF180 to request copies from NARA...
However, I would say that Van Hinton's Purple Heart can be confirmed without anything more than his Hospital Admission Card stating his injuries. The Purple Heart was awarded "to those wounded or killed while serving, on or after April 5, 1917, with the U.S. military." It was not a 'recommended' award, and was entitled to those who met the criteria (which he did).
So knowing that Rev. Porter met the condition, and that all contemporary sources mention him having the award, you can be reasonably certain he was in fact awarded the medal.