Considering your stature, in the Yamaha stable, instead of the MT-15, we'd recommend looking at the new XSR155. While both are mechanically near-identical, the XSR is a more spacious machine than the MT. Since this will be your first bike, the XSR will prove to be the most manageable and approachable. Thanks to its lighter weight and unintimidating power output. 

The Bajaj Pulsar N160 you're considering is a good option, but it will be the slowest of all the bikes you've shortlisted. However, if all you're going to do is potter around town, then getting the Pulsar makes sense as it is the most city-friendly bike here. 

Coming to the two Pulsar NS models, the NS200 will feel quite sporty and engaging while still being friendly enough for city use. However, the bigger NS400Z isn't the most city-friendly machine. Also, it will return lower fuel economy owing to its larger engine. 

The Honda CB350 models are very different to ride, thanks to their neo-retro leanings. It will be the most comfortable and relaxed machine of all the bikes you're considering. Lastly, the TVS Apache RTR 310 is actually quite a capable do-it-all machine, and will give you room to grow as a rider, too. 

Since you are considering multiple bikes with different riding styles and at very different price points, we'd recommend you first decide on your budget.  After that, choose within that range accordingly. Also, take a thorough test ride of everything you shortlist. 

Depending on your usage and the look of the bike you prefer, either of the bikes you are looking at will be a great fit for you. The Bajaj Pulsar NS200 is a great entry-level performance naked bike and will be far more comfortable to use daily due to its upright ergonomics. However, if ridden enthusiastically, fuel economy will take a hit. 

The Yamaha R15 M is the top model in the lineup, and its ex-showroom price is above Rs 1.80 lakh, which means it is quite a bit above your budget. If you do decide to stretch for the R15 M, you will have one of the sweetest, most capable beginner sportbikes around with a great look and feel. However, the latest R15 models are very committed in terms of their riding position. So, if you are going to use it regularly, you will need to put up with a seriously uncomfortable riding position. 

Instead, if you want similar performance, fuel economy and reliability with a good dose of daily practicality and a much lower price tag, check out the Yamaha XSR155. This is essentially an upright, neo-retro version of the R15 and will serve you just as well. 

A test ride of these 3 should help you determine which is the right machine for your needs.

A good upgrade without sacrificing mileage from your 100cc Platina would be something in the 150-160cc space, like the Bajaj Pulsar N160, TVS Apache RTR 160 4V, Suzuki Gixxer, Honda Unicorn/SP160, or the Yamaha FZ lineup. If you want to go beyond that, the TVS Apache RTR 200 4V, Honda Hornet 2.0 or Bajaj Pulsar NS200 will fit the bill. Take a long test ride to see which option suits you best. 

There are two types of bikes you can consider - sporty, liquid-cooled 160cc streetfighters and air-cooled, sporty-looking 160cc commuter bikes. In the former category, your options are the KTM 160 Duke and Yamaha MT-15, while in the latter, bikes like the Bajaj Pulsar N160 and TVS Apache RTR 160 4V can be considered. 

If you don't mind lower fuel efficiency, then the Bajaj Pulsar NS200 can also be a fun option within your budget. Another option that can be considered is the Royal Enfield Hunter 350, which will have a very different engine feel from any other option listed above, but will be comfortable and decently fuel-efficient. Something you can also consider if you're open to an ADV is the Hero Xpulse 210, which ticks all the boxes you want.