1. Built DFHack, RelWithDebInfo, on a fresh install of "df_47_05_win".
For what it's worth, you can just clone the "df-structures" respository and run codegen.pl directly - there's no need to build all of DFHack too.
In fact, it's probably
better to clone df-structures directly, since that way you can be sure you're looking at the absolute latest definitions.
5. File -> Load File -> Parse C header file..., select codegen.h.
7. File -> Script command..., paste in MakeName statements. Confirm _pause_state exists in Names window.
Apparently, you need to do these in the opposite order - first run the MakeName statements,
then import codegen.h.
Fortunately, you don't need to start over if you've gotten this far already - just import codegen.h again and it'll fix it.
You can also edit the structure XML files, rerun codegen.pl and codegen-c-hdr.pl, and reimport codegen.h in order to update the structure definitions in IDA.
I can add the structure map_block_column to the Structures window. Right-clicking the value gives an option for [r8+map_block_column.plants.ptr]. (The 't' option doesn't appear in this menu, but the shortcut works while the offset's selected. UX annoyance.) Right-clicking on the next one gives the option [r8+map_block_column.plants.endptr], so IDA seems to be pretty smart about that.
When you right-click, do you see any key name in the right column of the "Structure offset" menu item (or in any of the other menu items, for that matter)? It's possible that's something I manually configured in my own installation, since I believe it was a default setting in IDA 5.0.
9. Filter for sub_140CF0F90 in the function menu and double-click it. No named addresses present.
Unless this is another one of my custom settings, you should be able to press "g" to open a "Jump to address" prompt, then you can type in either an address (such as 0x140CF0F90) or a symbol name (sub_140CF0F90).
There are zero results for "getPlantAtCoords" on the internet (including your post and mine,) so that's kind of puzzling. (Tried Google, DuckDuckGo, and GitHub. At least Bay12Forums can find my post.)
That's because I made up that name myself, based on its apparent function. After all, we already do the exact same thing with the names of fields in df-structures.