I know you say that you are using 5e rules, but would it still be d20 roll under attribute or d20 roll high against a DC? But whatever the case, color me deeply intrigued by your project.It's still pretty aggressively informal at this point, since I'm not anticipating being able to start until 2021 (and who knows how much more delay there will be due to coronavirus). But, basically
-Make characters and design the village using the playbooks.
-Convert characters to broadly use 5e rules. 6 classes (Warrior, Rogue, Mage, W/R, W/M, R/M). The playbook gained features provide an extended background that guides skill choices and special class features. I have a bunch of rules modifying the 5e core, probably beyond the scope of this post.