Level 0 Weapon Proficiencies
As we discussed, the rules are clear that level 0 characters are somehow proficient in any weapon they pick up. The question was put to Goodman himself, and he explained his reasoning, which is good enough for me. It may not be the most logically cohesive rule, but it eases 0-level play, so thus we play. D20 for all to-hit rolls at level 0.
My house ruling on proficiencies upon hitting level 1 is slightly more generous than the RAW, which states your level 1 proficiency as the “last weapon used”. Instead, at level 1, you are proficient in 2 weapons: 1) your starting weapon or starting weapon type (i.e. dagger if scissors), 2) any one other weapon you used during level 0.
Thus, if you are a gravedigger with a shovel to start, and along the way you use a hammer, dirk, and short sword (picked up from fallen comrades), when you hit level 1 you are proficient in your old shovel (staff), and one of hammer, dirk, or short sword, your pick.