Wanting to Make One Shot Modules

I am wanting to turn a few of the dungeons I've built into one shot adventures that others can run. I was wondering some tips on doing this so I don't run into any legal trouble as well as wondering how difficult it is to make an adventure compatible with Roll20's Marketplace rules. I've read the rules but wanting to have conversations with people about it before getting too far into the process to make sure I understand everything. I have original adventures written by me for my homebrew setting. Maps made using Inkarnate (Looking into what is needed for a commercial license with them). I'm confused when it comes to the monsters of the dungeon and what the legalities of using them is. Do they all need to be homebrewed? Can it be as simple as renaming/reskinning the monsters? Any other rules about publishing a module I need to know? Layman's terms please. I've looked at the official rules and understand the gist of it but I'm hoping to have conversations with people that already understand the process before I launch into making this happen.

The "too simple" version: You must have a license for everything you use that is not made from scratch. Art must be licensed. This could be a "free" CC0 license, but without a license (and following its terms!) you cannot use it. Art created by an app often needs a license. Some apps, like the GIMP are really simple with what you create. Others like Inkarnate require a purchase (if I recall correctly). You must follow the requirements of the game system you are using. 5e products on Roll20 require following the Open Gaming License from WotC. This means you can only use content from another OGL publication. If you want to use something from a WotC book, it must  be within the System Reference Document, a small subset of what you can find in the PHB, MM, and DMG. A copy of the OGL must also be within your product, and you declare what is released under the OGL (for others to use) and what is designated "Product Identity". The product needs a high level of polish. Buy a product or two (or get a few free starter adventures like "The Frozen Sick") and see what goes into it. All of the adventure text is in handouts that cross-link to each other and to the other journal objects. All maps are set up and ready to play, with tokens linked to character sheets, and Dynamic Lighting set up.