Voltage levels of green/orange are also important.
If fuel level senders are really new then good, doesn't look very old.
If they are used it's possible they have similar problems than originals.
But not exactly, so new values should differ more or less.
Wire wound resistors, that those senders probably are, have a possibility to short circuit partially for what ever reason.
There some rounds contact their side buddies.
If so then meter's range will shrink and it retain its position when gauge goes over shorted section.
Low fuel circuit is most likely a voltage thingy.
Means that you can probably test it with a trimmer.
There you connect a trimmer over car battery, use high ohms enough.
And connect center tap to green/orange that is NOT going to anywhere else than to low fuel circuit.
When ohms between center tap and ground goes high enough the light turns on, so low side emulate gauges and high side the level meter.
What kind of a project is to see behind the meter block?
If black/white is ground then the circuit can be the opposite.
You can try that earlier trimmer between battery + and normally connected green/orange.
But then you must remember that you can almost short circuit the whole chain.
If tanks are full and trimmer is zero the resistance is only that 6.4 ohms and current is 2A.
This is why green/orange voltage is important.
Current driven level meter is probably mA range.
If we assume that empty level is 5% and know that it's also 300 ohms we can draw a line to full level.
But that missing 60 ohms is disturbing, to where that should be added.
If level meter is a voltage meter that 60 ohms can be missing from the top, but it can't be alone or that 6.4 ohms and 2A is back.
If empty level green/orange voltage is just few volts then everything is fine again.
Digital potentiometer and microcontroller is not a biggie.
Arduino Nano is enough.
Arduino Nano 33 IoT has a true analog out.
ATtiny85 has only 4 analog in pins.
Upper and lower tank gauges can go to A6 and A7.
Trimmers for adjusted levels to A1-A3, ATtiny85 is too small.
PWM or analog out to level meter driver, level shifter to 12V is possibly needed.
Fuel low light is different, but it's a simple on/off thing, so any digital pin will do, maybe a level shifter is needed here also.
If there are not enough installed wires fuel gauges can remain in series.
Then ATtiny85 is also back in.
Top is not adjusted.
Others are just matching values for half tank, fuel low and bottom ohms.