The 115 is a 646 engine. Very doubtful it would have a DPF.
The 2012 is a 651 with DPF.
The 646 would never meet the emissions rating of the later model Vito, so I don't see how it could meet MOT requirements for that alone.
Then you would need the ECU to go with the 646 engine, and communicate with the SAM in the 2012.
The loom would need follow the 646 also.
All doable, but no easy task.
But it would still be an MOT failure, imo.