Southern Alaska coastlines issues

You will need to post a screenshot here rather than refer to another site which most will not have a login to.

In general you put more geographically specific scenery like airports above less geographically specific scenery like regions or countries.

Saying that, PASI is in Alaska and that area is not covered by UTX USA. You also do not specify which simulator you are using. Finally, Orbx products are well known to change and overwrite core simulation platform files like Terrain.cfg which are used by many other scenery product like UTX. This means that installing them will cause visual issues such as you describe. In the case of UTX you can just restart the UTX Setup Tool and it will automatically re-add in the Terrain.cfg entries it requires. You'll need to check with the developers of your other scenery products to see how they cater for how OrbX changes the core simulator files.

Jeff