While searching for a programmable supply to use for the LiPo charger, I discovered the BQ25703A from Texas Instruments. It is a very feature rich part that can charge 1-4s LiPo's from a USB PD based input (5-20V). Which means it is a programmable buck-boost regulator. It also has a max output of 6.35A which is also programmable. The programming interface is I2C.

For supporting components, it will need a 3 MOSFETS that can handle 6.35A, a couple of smaller FETs, an inductor, some capacitors, and a couple of shunt resistors for current measurement.