-I'd stick to the one next to the ballpark.
The city's downtown charm largely rests along Queen and King. Distillery District is nice but the surrounding area doesn't have much life. Little Portugal is good but it's far from the ballpark.
-I won't gamble on kijiji, you assume all the risk of being scammed. And the prices are almost always adjusted for stubhub fee and exchange rate, so not worth the risk. 3rd baseline is a great spot anyway. I suggest if you can, get a lvl 200 3rd baseline ticket.
-Any ticket allows you access to the concourse area of any part of the park, including the flight deck. I recommend you go early, and make sure you have a strong bladder or people to save your spot.
-You can take the TTC bus/subway route which is longer, or you can use the UP express train which is very convenient and affordable. It also takes you directly to union station which is not far from the ballpark