Firstly congratulations on your upcoming wedding. New Zealand and Bora Bora are great choices for the honeymoon, though January is peak season so you're wise to start planning early.
Since you only have 6 days in New Zealand, I would recommend dropping the car idea and flying between the major stops - Auckland, Wellington, Christchurch, and Queenstown - to save time. Otherwise, you'll spend 90% of your time in a vehicle, suffering from jet lag, with little time left over for the sights. You can always satisfy the need to hit the road on day-trips from each place.
Even then 6 days will be tight, and in the interest of having a more relaxed honeymoon, I would suggest dropping one of the 4 places. From Chennai, you'll most likely fly into Auckland, so we can't drop that one (also your flight to Bora Bora will probably be from here). Christchurch is the least interesting of them - if I had to pick one to drop i.e. - so lets drop that one.
So I'll pick a really interesting place to stay in Auckland, Wellington, Queenstown and Bora Bora:
1. Auckland - Peace and Plenty Inn - Devonport is known as the "village" of Auckland because its history long proceeds the arrival of the Europeans, back to the times when Maoris ruled this area. That feeling of history, and of being in a more intimate part of the city, is brought to life in the superlative and romantic B&B. Set in a lovingly restored Victorian mansion, its a place that still proudly serves high tea (on Saturdays and Sundays), decorates its rooms with thoughtfully chosen antiques (chandeliers, fireplace screens, steamer trunks) and serves a sumptuous breakfast. The host is an ex-pat Brit who shares her love for her adopted country with great passion. Shops are around the corner and the home is surrounded by lush gardens.
2. Wellington - Ohtel - A small, chic, ecofriendly, waterfront hotel packed to the gills with collectible mid-century modern furniture. It's unbeatable value, a total sensory experience, and one of my top picks for something unique and memorable.
3. Queenstown - Remarkables Lodge - The hosts, Brian Savage and Colleen Ryan sailed the world for 10 years chartering their yacht, came ashore in Queenstown and took this well-established lodge and re-invented it from the ground up. With an understated level of class that puts it above many, it's a top retreat tucked into the foot of the very remarkable Remarkables mountains.
4. Bora Bora - St Regis Bora Bora Resort - Note: this will be very expensive. One of the island's swankiest hotels. I did try and find the quirky, quaint type of places, but seriously Bora Bora is one place in the world where you shouldn't miss out on staying in the finest hotels.
Hope this was useful. In case some of these are not available for your dates, I'll be happy to recommend other places. And of course, planning the day trips, activities, places to eat, etc. Look forward to hearing back from you.
Happy travel planning,
Congrats on your upcoming wedding!!
Honestly 6 days is too short for New Zealand, if possible try to increase it to at least 10 days.
For 6 days you can fly into Christchurch and fly out of Queenstown. You can drive from CHC to Queenstown either via Mt Cook, West Coast - Glacier region or Dunedin. Each place is different. Best is via West Coast but it involves long drives.
Other option is you can spend 6 days in Queenstown and do day trips to Wanaka, Mt Cook and Milford.
I would be able to suggest hotels, once itinerary is finalized. However Queenstown should be definitely be in your itinerary.
For Queenstown I would suggest Rees Hotel and luxury Apartments.
It is easy to get vegetarian food in New Zealand. I am also vegetarian and had no problem at all. Each place at least have few veg items on the menu.