hi rickyrich,
1. the power window can only wind down automatic, wind up u need to hold the switch.
2. try to remove ur spare tire then ur hand can access into beneath of the seat, try to search/look around there by putting ur hand in...
3. did u change ur steering wheel to smaller size? use diff size tire? use diff rim size? if no, send to a workshop, something is wrong with the power steering pump or steering rack. imho, try power steering fluid change first before the pump and rack.
4. yes it's normal, my kenari on empty tank can only pump around that also, i guess the balance should be the reserve tank.
5. previously my driver side door have weird sound also, but no idea mine and urs are the same, my solution by using duct tape to stick my door lock hinges on chassis side; anyway, send to a mechanic that u trustable will be good, make sure he doesn't do funny funny stuff, and sorry to say but i have no confidence perodua sc can solve it.

hope my info helps! 

full tank how much ?

u r welcome! 
1. for my car, i change it to smaller steering wheel + myvi se rim which is wider (14X5JJ), original kenari is on 14X4.5JJ, so my steering wheel is heavier then usual; for ur case, maybe u can check what wheel size u r using, take a photo of the whole wheel and post here, then everyone can help, to notify whether it's wheel's prob or power steering prob. for ur question, if everything is alright and stock condition, the steering wheel is smooth.
2. not to say hide, the connector might dropped inside, so just remove the spare tire and use a torch light then u can find it; if not, it's removed.
3. wow ur auto runs 400+-km? it's nice to hear that! mine can only run 300+, so 400+-km is consider good for a kenari! 

Bro, i dont want to say anything more. But is good that you can do comparison if you have a few set of sport rims and test it out.

Since i already left the tyre shop and venture to other sector, i can just said that if the wheels diameter is not important, why there is this kind of data provided by the tyre/rim manufacturer itself?

http://customwheelsmarket.com/rimwheelwidth1.html

Each tire has a specific rim width range on which the tire can be mounted. Failure to follow rim width recommendations may result in poor tire performance or possible wheel and/or tire failure.

Choosing a wheel near the middle of the range will give a balance between ride quality and handling. A wider wheel will improve handling at the expense of ride quality, while a narrower wheel will improve ride quality at the expense of handling. Consider these compromises when selecting wheels.

What is your sport rim width? If between 4.5JJ to 5.5JJ should be no issue..