All of those sound like really big modifications. As in, you’d have to change a lot of stuff to get it to work.
The simplest of those is #5 - the basement. It isn’t easy, but other ideas on the list are harder. It is the only one you could add without compiling the game from source code.
You have to first define the new terrain in data/json/overmap_terrain.json. Copy the existing entries for refugee center, then modify them (change names).
Then you’d have to add them to data/json/overmap_specials.json. Find the refugee center there (named evac center) and modify it so that it references the entries from above. The big block with lines starting with “point” is the part you’d want to modify.
Then finally you’d have to define those entries. You could copy and modify the files in data/json/mapgen. LMOE shelter is a good example, because it has both aboveground and underground levels.
Another one that would be relatively doable is #2 - the ant tranquilizer. This time you would need the source code of the game and means to compile it.
You’d have to define a new item use function in iuse.cpp and make it get properly added to items in item_factory.cpp. In this function, you would ask the player for adjacent tile, check if this tile contains an ant queen and make the queen friendly if she exists.