Check the 3rd brake light bulb in the rear window, quite a common cause of that warning.

On face value replacing coils 2 and 3 should fix it but I'm quite dubious about that and don't like wasting money. If you have your own OBD dongle which are very cheap you could try swapping 1 and 4 for 2 and 3 and check codes again, another short and open message could confirm bad coils. Coils go bad but I'd only expect one at a time, I carry a spare from an old car that I can press into service if needed to get me out of trouble, these coil on plug systems can be fairly interchangeable but cunningly the makers love to fit different connectors in the hope users never find out.

I think the 2500 rpm is encoded into the engine module, quite clever too methinks as I can just jam something on the pedal when I want to check something at home that needs revs. The limiter must be released when moving in gear although I still rarely go over 2500 rpm.

Often something like that can be caused by vibration, trying a better quality bulb can help or if you're like me and want something up to date then LED lamps should be pretty near immune from vibration drama. The downside if you have a FLX like mine is you'll have to put about a 1200 Ohm resistor between the two 3rd brake light terminals to provide an earth path for the tiny check current that sets off an error lamp on the dash.

Oddball issues like this trigger a check the grounding alarm with me. If you see any connection to the bodywork then check it's secure.

Knock sensor is a PW811757 but before you replace it try unplugging it and giving the contacts a clean, perhaps even merely wiggling the connection will help.
Dunno about the price, I see eBay locally want AU$90 for it so I imagine that would translate to about 90 Ringit but I'll bet an aftermarket equivalent if found will be much cheaper.

Parts sometimes just fail, since your car sent a code specific to the knock sensor then that would be the part I'd be checking.
After I posted this I looked a bit more and saw a much cheaper one that looks the same that was listed as an aftermarket one for a different make, so cheap at under AU$6 that I ordered one and will check it for operation when it arrives and if good carry it as a spare just in case I ever need one.
The knock sensor senses pre-ignition or knock/pinging and throws a signal to the ECU to retard the ignition a tad thus preventing engine damage, it does this before we can hear it so it's a good thing, hopefully the ECU falls back to fail safe mode upon a sensor failure to prevent damage but the downside will be less power and worse economy, so it's best to react to a check engine light event ASAP rather than pour extra money on fuel in the meantime.
I also haven't yet checked where the sensor is located on my Daisy, so if anyone here wants to post a tale about it I'm all eyes.

My FLX doesn't have any cover over them, I just open the boot and have access.

I would never skim mine, it's only a recent profit increasing thing for service places, if by some chance a rotor has a condition that may warrant skimming then it's still a better option just to slap a new set of rotors on, they've dropped enough in price over the years to make sense.
The aftermarket replacement pads specced for the FLX have a squealer tang yet Daisy's original pads never had them so toss a coin on that one but I put a set meant for a Daewoo Kalos which are the same but a fraction of the price on Daisy when it was new, the cheap Protex Blue pads I fitted have a way superior feel than the originals, more bite for the same pressure.
You lucky stiffs in Malaysia don't have any issues trying to find parts for a rare vehicle like I do though.

Check your fuse and if that's OK then life gets hard, often gremlins are from bad grounding to the frame but good luck tracking the wiring.
I've just checked my FLX for the fuse to the number plate lamp, which also does the tail light so I suppose if the tail lights are working then you can scratch the fuse as being an issue. I've arrowed it in this picture, oddly it's labelled RH but it does the rear of the car, the one above it is labelled LH but does the front parkers.

Well done to spot that break, that's a really weird one.

Try pulling the side air vent and then put a bit of lube on the contact surfaces where it meets the dash panel. My Daisy had an odd noise on the drivers side a long time ago and doing that to the driver's air vent fixed it, I just use a trace of silicone grease.

If you meant the odometer part of the gauges then annoyingly it's only lit when the lights are on. I modified mine to be always on when driving so I could see it (old eyes need help) and may have posted what I did here but it involves a couple of diodes and cutting a wire.

I checked info I could find when I bought Daisy and it looked like they're pretty easy to work on, any real problems would be due to tradesmen having an innate fear of anything different.
About the most awkward thing I've seen is having to procure a long armed puller that has legs that are thin enough to fit between the balls of the shaft bearing.
The pushbelts are readily available on Aliexpress but these Punch VT2 transmissions are claimed to be good for 200,000 km minimum service life, things would hopefully become more available and cheaper by the time more units reach that point. Even as it stands for me now obtaining EZL799(a) fluid is a difficult exercise despite many cars being CVT now.

According to my service book the IAFM+ engine which the FLX (or at least my FLX) has is good for 120,000 km or 96 months. The earlier campro engines are 90,000 km or 72 months. I'd still be inclined to change it before 120,000 km though, timing belts are always timebombs in an engine, or at least in an interference fit engine.

Yes very different and be very careful, don't even rely on a workshop knowing how evil it is to put common ATF in a CVT. CVTs can be ruined by using ATF ours need fluid that's labeled EZL799 or EZL799(a) without that marking on the container avoid using it.
From what I've gathered unlike common automatic transmissions CVTs rely on friction between the pushbelt and the sheaves, so need an oil that provides added metal to metal friction, slippage here will damage the belt and sheaves.
Word of mouth here is that the filter is good for two oil/fluid changes, so ignore it at the 50,000 km change.

I'm still waiting for it to begin appearing on shelves, and it's annoying that with so many CVTs about now that traders aren't stocking it, although I think one brand's fluid is now available, which doesn't help me as I'm not a fanboi of them (don't worry it's an Aussie company so you won't find it).
A Proton dealer would be a good place to look but I fear the only one within a day's drive from me would stock that said maker's stuff, which is what they use for normal servicing and another reason Daisy has never been there.
Last time I checked our oil companies web sites here for suggested fluids they were all indicating 7.9 litres of Dexron 3 was correct for a FLX, quite wrong of course and I wonder if they'll pay compensation for the damage caused.
Our CVT is a punch VT2 and I imagine when the time comes for a new filter I'll be checking out what other cars use it and perhaps that'll help me to find one, something that's easy for you Malaysian owners with Proton being a fairly common brand, unlike ultra scarce here. As far as I've seen Daisy is the only FLX in town but there's also a BLM about. Quite a shame really as I read tales of woe often written about the *better* brands, while Daisy keeps reliably chugging along.

I can buy EZL799 online or an oil company depot should have it (or be able to order it in) but as yet I don't need it, although it'd be nice to have some on hand in case I need to add some.
The killer for any car maker is if a workshop uses the suggested fluid and causes terminal damage to the transmission, the end result regardless of who accepts liability is the car maker gets a bad reputation despite the transmission being built by a 3rd party maker and incorrect procedure being followed. Protons here are a nearly as rare as unicorns and workshops are likely to be stunned like a rabbit in headlights when tasked with doing any work, a scary prospect.

You're good.
Time flies, two and a half years now since I bought Daisy and started posting here.

It's probably fine now, my reluctance is from some cases over 30 years ago that have had a lasting effect on my preferences.