Hey Himanshu,
I'm also in Calgary. Certainly there are opportunities in Calgary. I agree that it is better to add more than 1 door per property, as the cost of a property here is relatively high relative to rental rates.
However, since this is your first property, it might be best to get something close to you that you could oversee and most importantly learn from? I'd say the value of the first one is not necessarily the return on investment, but more so the learning and experience that you gain.
I've got a couple legal suited up/down duplex's here, and have some learnings but the biggest challenge is going to be to get a worthwhile valuation - making the purchase price even more important (if your goal is a successful BRRRR). Regular side by side duplex's will be valued higher. With that said you can still create cash flowing properties with a number of strategies, and given enough time, the financials usually work themselves out. Part of the beauty of real estate.
To answer your 2nd question, my preference is always to rehab properties as it can be tougher to get a good deal on a place that is turnkey. Also, I just like the process, and enjoy creating beautiful places. Maybe not always the cheapest or absolute best ROI, but creating those wonderful spaces is one of my goals in and of itself.
As for Q3 - locations. Similar to most cities I'd say. Stick to places close to transit and universities, or employment hubs. In Calgary, Brentwood, Varsity, Capital Hill would be my choices amongst others. But you can find opportunities in lots of areas too.
Anyway, good luck!