In the book of boba fett, episode 5, we see a BD series droid, a bipedal droid with a head that looks like binoculars. We can infer that GENERALLY droid come in phases, for example r2 units were the main navigators for the rebellion/new republic, but by the time we get to the sequel era, far mor BB droid are in use. We also see battle droids get banned by the galactic senate after the clone wars, but the empire soon after has K2 series droid as opposed to the B1s. Knowing that droids in this franchise are phased in and out, we can infer that the BD droid we see is from the end of the republic era, and knowing that we never see one in rebels, rogue one, solo, or the OG trilogy, they had to have been phased out/destroyed for the most part. Now how did a BD droid get to tattoine, or even into the hands of Peli Moto? A Jedi (maybe even cal kestis) crashes into tattoine, jawas steal the droid, Peli buys it