Yours is a two part question, if I read it correctly.

So, part one: NO, it is not appropriate to wear any part of the service uniform (US Army, Navy, Air Force, Coast Guard, Public Health Service, or Marine Corps) with civilian attire if you are still on active or reserve service status. As a civilian, mixing parts of the service uniform with non-uniform items looks like a costume and gives the impression of having no respect for the uniform.

Part two: McVarmit's photo shows how miniature medals should be properly worn on a Prince Charlie coatee, or on a tuxedo jacket or tails coat.

Medals are appropriately worn with civilian black tie (PC or tuxedo) when the host of the event makes it clear that the wearing of medals is appropriate. The invitation, or admission ticket to the event will clearly state "Black Tie, decorations". If the invitation does not mention decorations then no medals should be worn.

While on the subject it may worth mentioning that neither the Prince Charlie coatee nor miniature medals are ever worn during the day. For day time wear only full size medals are to be worn, and they are worn in the same manner as prescribed for miniature medals worn in the evening.

Service ribbons are not worn with civilian attire except by bandsmen in uniform, or para-military organizations, such as SAMS, who wear them on their distinctive uniform shirt.