I can't help you very much. About bot AI, maybe you may ask to Graion Dilach
For some documentation about how bots work, you can take a look to the "external links" (which are mostly Q3 related) you can find here:http://openarena.wikia.com/wiki/Bothttp://openarena.wikia.com/wiki/Bot_playThis PDF
looks interesting for your research.
There is to say that OpenArena did some changes to the bot part
(maybe to avoid some possible copyright problems, I'm not sure), so if you used a bot designed for Q3 in OA 0.8.5, it was not able to correctly select weapons. OA 0.8.8 includes a bot compatibility patch that allows bots designed for Q3 to behave correctly when used in OA.
Someone (I hope Graion will find some time to do it!) should write a bot-writing manual, because AFAIK at the moment there is not much documentation that explains how to create a bot in the OA format instead of in the Q3 format.
This to say that I don't know where you can find detailed infos about the differences between Q3 and OA bots in game logic. I don't know if and how the differences include pathfinding.