Here's what you could do. Have a variable that tracks available jumps, set to 2 upon touching the ground. If the player jumps, that decreases. The player can only jump if the counter is greater than 0. Double jump, easy enough.
For coyote time you use a timer (behavior or variable). If the player leaves the ground, the timer starts. When the timer runs out, decrement the jump counter. If the player jumps, cancel the timer (if running) and decrement the jump counter.