Could this flight be qualified for a FAI record attempt if documented prior?

Answer is NO.  The total length of AOPA-Japan route is 31,824km, which falls short of 36,787.559km requested in section 5.3.6.1 of the FAI Sporting Code.  Baker Lake(Canada) CYBK’s latitude of 64 deg 17 min North was close to the 66°33' limit of polar area avoidance rule required in section 5.3.6.2.

FAI Sporting Code excerpt

      5.3.6. Speed around the World (Eastbound and Westbound)

          5.3.6.1. The course, including the control points, shall be approved in advance by the NAC's

          concerned. It must start and finish at the same aerodrome, crossing all meridians. The length of

          the course shall not be less that 36,787.559 kilometres (equal in length to the Tropic of Cancer).

          5.3.6.2. All control points must be at a latitude of less than 66°33' (outside the North and South

          Frigid Zones).

          5.3.6.3. If due to unforeseen circumstances the final landing cannot be made at the aerodrome

          of departure, the aircraft may fly to an alternate aerodrome lying beyond the original one (at a

          greater distance from which the start was made).

          5.3.6.4. Intermediate landing places, turn or control points must be declared and agreed in

          advance with the NAC's concerned.

          5.3.6.5. Any time spent on the ground between start and finish shall be counted as flying time.

          5.3.6.6. Refuelling on the ground or in flight is permitted.

          5.3.6.7. Repairs or replacements of aircraft components and engine(s) are permitted except that

          the wings and fuselage may not be changed.

          5.3.6.8. Crew members may not be changed during the attempt. However, in the case of an

          emergency a crew member, other than the pilot-in-command, may leave but must not be

          replaced. Passengers may be changed during the attempt.

          5.3.6.9. The start time shall be the time of take-off ; the finish time shall be the time of landing.

          5.3.6.10. Record attempts will be categorised as follows :

          Category A - Without refuelling in flight

          Category B - With refuelling in flight

          5.3.6.11. In the case of an aircraft having the capability of refuelling in flight and attempting a

          record under Category A, adequate evidence must be provided that refuelling in flight did not

          occur at any time during flight.