I don’t really know anything about CAN, so I’d recommend checking around what other people are doing. For example MicroSpora uses CA-IF1044. And here’s some info on the programming side A new CAN communication standard for SimpleFOC - CANCommander
For other components, the Mosquito buck converter is called LMR14006YDDCR (LCSC part number C477919), and it needs a bunch of passives (open that MosquiNo board I linked before in EasyEDA and copy/paste). It’s good for space-limited designs because it switches at higher frequency than most bucks, so it can use a tiny inductor.
If you plan to actually use the robot arm for anything, I’d recommend at least 14-bit encoders. With 12-bit you can always feel a jitter in the motor when holding position, which will wear out bearings over time, in addition to hurting its accuracy. AS5047P is good, and $3.20/pc for 10+. But for 40 cents more, MT6835 is fabulous with 21-bit precision. The difference in jitter is nearly imperceptible to my hands, but visible on the DRO of my milling machine (the axis with MT6835 has a stable micrometer position, whereas AS5047P has a few micrometers of noise).