Bot's could be added, but in their current state they wouldn't be able to traverse certain area's of the map.
TBH, i never tried adding bots, but i can imagine that they could have issues with some of the rather uncommon machanics in this map.
e.g. the random destination teleporter.
Other locations like the allmost invisible maze might not be an obstacle for the bots, since they don't see the enviroment like regular players.
@Rick: theoretically every map since you're able to change the mood of the map while editing.
Even cradle could make up a good Halloween map, it would be just a very complicated edit with lots of custom content.
like: turning all catwalks into wooden ones with hanging bridges and replace the dish with something like a giant creature mouth or vulcano beyond.
Using a nighttime scene ofc. and light up the rest with candles and pumpkin lights.
But in general classic maps that have a simple level of detail are best to edit.
Also there's a difference between a simple edit like i did with ge_stack_xmas which in huge parts was only a retexturing, decal and prop placement thing and ge_library_halloween which was built from scratch.
The reason for building it from scratch is simple, i needed that 128x128 units pattern and some space inbetween first and second floor for the displacements to work correctly.
In fact the whole upper level area consists of these little square blocks turned into displacement.
I'd call this kind of level building the minecraft approach.