1. Cabin light not always turned on when car doors are opened
Mine is the same, door ajar sensor not working after some period of use. Each door has independent sensor. Make sure you test them all. Can easily replace FOC in P2.
Personally I'd like those to be fix permanently. This is the second time I bug them about it.2. Rattling sound of loose parts on B-pillars.
Mine D pillar got sound, I tried many solutions then finally I bend the safety belt metal slightly, the sound is gone. B pillar is easy to dimantle, try DIY.
I've insulated all pillars with Insulflex previously to prevent the plastic from rubbing to the metal, hence the sound, but B-pillars are from another problem.3. Brake and acceleration pedals vibrate when wiper is running or when there's external loud noise.
This sounds damn funny, mine is the same, but I don't care
I don't like it. It gives the feeling that the whole damn pedal can tercabut anytime... That may also explains problem 7 where the spring came off. Rattled until it came off...?4. Front suspension noise when going over road humps.
Mine too, after that found out it was the protective gaiter made the sound. So i don't care , maybe your case different
Second occurrence... I want the same - to be fixed permanently.5. Loud burst sound from air-cond compression when activated.
I thought all Alza has the same shit like this?
Heard of Russian-mafia style execution when you start your car, the car explodes...? This is something like that...6. Soft-voice over bluetooth calls on phone during high speed where engine and road noise are intruding.
I fed up with the bluetooth, our cabin is just too noisy to make it works, unless we stop at traffic lights
No comment. Perodua is lousy with insulation...7. Acceleration pedal spring came off.
Calm down.. This isn't ferrari
It's not about ferrari. It's about safety...8. Rear brake noise
Just ask the foreman clean the drum brake
Foreman was puzzled why this problem only occurred now when it should have been many months ago...
I don't even know how to reply him.9. Rust issue near battery in engine compartment
The yokohama shit water leaking, I already change to Maintenance Free battery.
The problem is, my battery just don't wanna die...
10. Check spare tyre holding cage for signs of weakness/buckle.
I hope mine is fine on this.. never really inspect that before
You better go check before you become the next n8210... 
11. Gap near quarter window where rainwater may seep in and causes rust inside door panel.
Mine too, but my door is not rusted.. I thought myvi or other car also same? That's their so called drainage system..
I've checked my other MyVi, none has it. My Kembara has that wind problem, but since it's no longer with me, I can't vouch for that.12. Weird paper-like noise inside main air-cond blower.
I used to hear that, after that found out is the air con fin wrong position.. Readjust the fin then ok..
It comes and goes...13. Noisy engine above 110kph
No.. I just haven't try to firewall solution this yet... but if I pump BHP Ron95 the engine won't be so noisy..
BHP and Esso no difference to me, the engine is plain harsh noisy. And they still wanna sell me that damn add-on instead of offering as a countermeasure. I've even asked them if they have better engine oil, I don't mind paying more. Firstly, they don't have, secondly they do not allow outside engine oil without voiding that damn warranty. Perodua means no choice.14. Steering vibration issue on uneven roads
My Orifice haven't come yet! That's a long wait..
I guess you're dealing with Perodua Authorised Service Dealer and not Perodua itself...? They don't even know shit of what they're dealing with here and say it's NORMAL to vibrate that way.