I have made some more changes, added islands like Wake Island, Soccotra, Canary Islands, added more cities in most regions of the world so Aliens might terror attack more places (not sure if they will use them in game, like how do they decide where to terror mission?), and packaged it as a mod: Globe Islands.
Works in OpenXcom 1.0 dev nightly and OpenXcom Extended 7.9.8 [2023-07-03] running in Linux Mint.
Note: To try this mod, start a new game. If you load saved games that were started without this mod the aliens may be using some of the old regions and waypoints.
Version Notes:
Version 0.2b: Changed country areas (used for UFO / XCOM activity calculation) to be slightly more accurate. Added alien mission areas for new Pacific islands.
Update 12 Aug 2023: Ver 0.3b - fixed region rules so UFOs should spawn missions in the new ocean areas and land on the new islands. Added a few more cities. Also adjusted country rectangles to include British, French, and US overseas territories like Guam, Hawaii, Falklands, French Guyana etc.