William Yorick makes the most out of its short supplies

First buy is Charisma for the extra ally. Then, Survival Knife or Eucatastrophe (for Jury-Rig), which makes Bury Them Deep more reliable and powers some comboes.

Police Badge helps both you and your allies, so it's a handy addition next. You may opt for Relic Hunter to have it along Cherished Keepsake if you don't spend it inmidiately (for example, to foster your seeker actions).