You can pay full amount in the first payment and get the car delivered based on the availability.
For more updates or information on Honda cars along with other latest, upcoming and most popular cars, log on to www.cardekho.com.
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.