Hello there.
You can go lower on the wattage without any problems. Only difference being is that it won't be as bright.
I have led festoons on my FRV. you need to put them in the right way round though or they won't work. I've never had a problem with mine blowing fuses because LED lights draw less current than a standard bulb.
It sounds like its "bouncing"
A spring would have snapped inside the lock mechanism and doesn't offer any more resistance inside the lock. A new lock would solve the problem in most cases. Sounds like the drivers lock because that's the master that tells the other locks to open.
I know the answer.
A can bus radio does not have an ignition. It works via your can bus system.
In your original wiring loom, you won't have one for your new radio. You need to find a new ignition supply near the fuse box and put a 7.5 amp fuse in line with the new supply. This will then go to the ACCESSORY WIRE, usually yellow at the back of your radio.
The loom on your vehicle would also be used for other vehicles with different equipment different to yours.
If there aren't any warning lights on and everything is working fine, there's no need to worry about it......