Is that possible to use MonumentAddons to make drop zones yet?

Not yet, sorry, been slow on making plugin features for quite a few months. This is not a very difficult thing to do, so I'll try do to it this month.

Merged post

I just pushed a change to GitHub, which you can test using the following link.

https://raw.githubusercontent.com/WheteThunger/MonumentAddons/master/MonumentAddons.cs

To place a drop zone, run the command maprefab dropzone. When you reload Better Chinook Patrol, if that monument is configured to be visited, it will now show a "HAS DROP ZONE" annotation in the server logs as verification.

You are the best!  I'll give that a shot and let you know if I have any issues!