We would recommend a three-row vehicle, as there are very few cars in which the second row of seats folds flat or can be removed. Two cars in which you can remove the third row of seats to liberate a large flat area are the Renault Triber and the Citroen Aircross X. 

Both are great options that offer comfortable rides and great space efficiency. The Aircross X is larger, more powerful and from a segment above, but the Triber is more affordable. Also it has a lower boot lip height, which will make entry and exits easier for your dogs. 

All things considered, though, the best all-round option for you is the Kia Carens Clavis, though it is more expensive than the aforementioned two. Not only is it a much better-rounded vehicle with more powertrain options (including an EV), it's also the most practical. 

It has a flat folding third row, which on its own frees up lots of space. Moreover, if you need more still, the second row will fold near-flat in the 7-seat version. You should be able to fit a mattress for your dogs with a bit of folding.

The recently facelifted Renault Triber and upcoming Nissan Gravite are both good options for your usage. Essentially the same car under the skin, they are surprisingly spacious given their sub-4m length and overall size. 

The advantage of getting a 7-seater in this case is that, for your occasional 6-seat use, you will be able to manage with this car, and for the rest of the time, your 4-5 passengers will be more comfortable, and you can carry some luggage too. 

As a commuter, its compact dimensions make it easy to manage around town. Renault and Nissan's quality and reliability have come a long way since the early days. Though not quite up to the gold standard of certain other brands, are not a serious issue in the slightest. 

The Punch EV is a good choice, too. But for the reasons mentioned above, as well as your 1,500km monthly usage, we'd recommend sticking to a 7-seater and an ICE vehicle.

Given your requirements, the Nissan Magnite and Renault Kiger are worth a look. There's plenty of space for rear seat passengers, and there is enough room for three passengers to sit in the back in reasonable comfort. 

You could also consider the superbly packaged Renault Triber. It's three rows of seats give lots of flexibility in seating, and the option to slide the middle row also means you can open up lots of legroom by moving the seat to its rearward position. 

Given your requirements and budget, you have two options. The Renault Triber is well-priced, genuinely practical, versatile and can accommodate up to seven passengers. But its 72hp, 1.0-litre petrol engine feels lethargic, especially when the car's fully loaded.

Alternatively, you could consider the Maruti Suzuki Ertiga. The Ertiga is more spacious, has a more powerful and refined engine and being a Maruti car, you'll also like the peace of mind it comes with. There are currently two Maruti Ertiga variants (LXi and VXi) that are priced below Rs 10 lakh (ex-showroom).