Wa alaikum assalam and congratulations on your purchase! I am from Lahore so can't answer your first two questions precisely. However here goes for the rest of them:
3: If you want to replace the front bearings, first make sure that they actually are the problem. Don't just replace parts because somebody told you so. (I am telling you this because a lot of times I've seen mechanics ripping off new car buyers by selling them stuff that they don't actually need). To check it: Jack the car up from the front (the front support arm in the middle under the engine) and grab your front wheels one by one at 12 o' clock and 6 o' clock position and try to wiggle it. If you find excessive play, only then you know that new bearings are required. If there is no play, your bearings are fine. To check for possibly worn front control control arm ball joints likewise, you can repeat the same procedure by changing your hand position on the wheels at 3 o' clock and 9 o' clock position. If bearings are worn out indeed in your case, get the break pans open and get them replaced. You will have to find a way for that in Pindi though, again.
4: Go for any DX-III type transmission fluid. Valvoline ATF DX-III Automatic Transmission Fluid would be good. If it isn't available, any good brand DX-III type oil can do. But be careful not to over-fill the transmission or your transmission seals will blow out on you. Here is how to check: https://www.pakwheels.com/forums/liana/22866-liana-owners-fan-club-491#post5003321
5: I can't help you for Pindi but for Lahore you can visit Bilal Gunj. Or for Peshawar, you can try Sitara Market. Don't buy second hand parts for your suspension, though. You'll not be a happy man if you replace your original suspension parts with Kabli ones. Guess how I know.
6: Fuel injectors are the same for both 1.3 and 1.6 L engines for Liana/Aerio. For correct part number and pictures, you can refer to my comments here: https://www.pakwheels.com/forums/liana/22866-liana-owners-fan-club-528#post5028926
7: Most of the times the power steering becomes hard because of contaminated power steering fluid or somebody replacing the upper small curved power steering bucket pipe that is an L shaped pipe connecting power steering oil bucket to the metal pipe below. If someone put a desi pipe instead of an original part, it will not bend properly and will be crushed at the point of bend once heated up by the engine. When this happens, your power steering will feel really heavy because power steering pump will have to work twice as hard to pump oil through the system. Get that hose checked and if you see a desi piece there, replace it before you have any bad experience on the road. Plus, also check out your power steering belt for wear. It's usually a good idea to inspect all the engine serpentine belts whenever you buy a used car.