Is it allowed to fly a right traffic pattern when a left traffic pattern is published (IFR)?
Yes, it is legal to circle north under IFR using "right" hand traffic and land on Runway 25. 

"Left traffic" refers to VFR traffic. Traffic patterns are generally flown at 1000' AGL. IFR aircraft don't fly traffic patterns unless they cancel IFR or are doing a visual approach under direction of an active control tower.   

An IFR aircraft on a circling approach can maneuver at any altitude (above the published minimum altitude), and in any direction, in order to align itself with the landing runway. .

When you are issued an IFR clearance at an uncontrolled airport, the IFR airspace around the airport belongs to the IFR aircraft. I think FAR 91.126 (a) General. "Unless otherwise authorized or required" would supersede the left traffic requirement.  

In this case it is mandatory to circle right because Circling south of runways 7/25 is not authorized. ("NA") 

If the weather was above VFR limits, and there was also a VFR aircraft in the area, they would have to fly a left traffic pattern and communicate to avoid conflicts.