So far, Honda CR V is offered only in petrol version and apparently, the diesel version of this SUV is right now under process. Honda CR V 2.4L 4WD AT comes with automatic transmission. Follow the to know the details of mileage and more: http://www.cardekho.com/carmodels/Honda/Honda_CR-V
It may be possible through outside car modifiers. However, since the car has been designed as a 5 seater, adding the rear seats will be tricky. They are unlikely to be comfortable and will leave you with negligible boot space.
You can find the engine no stamped on the engine itself, but if you are unable to locate it, you can also search it on the product information tags on the car, which generally found under the hood near engine bay and on the door frame.