Converting OSR to 5E or Pathfinder?

[DiscoSoup]

Hi, all. So I've got this game called Kaigaku. It's a hack of Black Hack. The biggest difference between Kaigaku and vanilla Black Hack (black vanilla?) is that you customize your character by inserting various abilities from your PC's school at even-numbered levels. These schools (called ryu in-game) are a lot like archetypes in Pathfinder or those variable class features in 5E (bardic colleges, primal paths, etc.).

I'm currently preparing an epic adventure for Kickstarter, called The Ruined Kingdom. I want this campaign to have as broad an appeal as possible, so I'm going to include monster stats and class abilities for White Hack, too. I'm considering adding support for other OSR games (it'd be pretty simple, based on reader demand). I also am open to porting monster stats and class abilties to 5E and/or Pathfinder. I'm familiar with the systems, but I'd like to get some words of wisdom from you rules mavens or anyone else who has experience with this sort of thing. What would you suggest? Are there any pitfalls? Best practices? Many thanks.

[thirdkingdom]

Maybe look at Frog God Games? They do a lot of stuff for multiple editions.

[DiscoSoup]

Awesome! Thanks.