Do you plan set Beach as primal location found under explore like lake or location found by exploring some other one (I do think desert or forest would be good point of start to find this area then, eventualy plains)?
TBH if have no plan so far. Just some random ideas, how this could possibly go:
I guess I would probably require that some locations have already been discovered (e. g. Forest, Plains and Desert discovered)
After that it'll either be primary or secondary. Not decided yet.
About the Ocean:
I think, I'll use the following approach:
When exploring the Beach for the first time, the Ocean and Deep Sea will be added, but the buttons will be disabled, if you don't meet the requirement to explore then.
Meaning:
If you either found the boat or if you have webbings on both hands and feet, you can explore the ocean.
If you have gills+webbings on hands and feet (or a fish tail, or: magical fish feet like a mermaid/merman) the Deep Sea button will be enabled.
As on Wyvern it would be something siilar to lcking both arms and wings slot so if PC use TF to change either of this body parts wyvern wings will be lost? Porbably it would also mean some jingling of code to show properly in appearance screen but I trust that would be your smallest issue with wyvern wings ^^
I already have some ideas, how I would probably implement wyvern- and bat-wings. One of my biggest problems atm is: Will it result in changes++ or in changes += 2?
PS: Beginning with today I'm officially a Computer Science Expert: System Integration (in german: Fachinformatiker Systemintegration)