Wiring in series divides the voltage, so the more leds you have in series, the less each one gets so the dimmer it gets, and apparently 5v divided by 4 is not enough for each led's minImum voltage requirement.
Try the same circuit but connect the + side to batt + pin, like 8pin + for elevation motor. If they light up, they'll still be dim though.
My recommendation is either get all new leds with same specs (but different colors) and then you can calculate and add proper resistor. Or connect headlight leds to 1 output on asp, and tails to another. There's plenty light outputs to choose from: headlight, taillight, aux light, even mg2 can be used if you're not using it for mg. Asp is really versatile as long as you think outside the box
