1- ASAIK the keyword fix aiscript limits are; 256? total keywords/aiscript, 64 keywords/action test block, 32 action test blocks max.
2 - When you add any scripted entity to the script file it seems to take the next entity number starting with the one after that for the game manager (script_multiplayer, #73 in this map). That displaces all the map's entities that the mapper added after the script_multiplayer. So if adding fake_funcbrushes crashes FritzBot ET I suspect you forgot or missed re-adjusting one of the action ent numbers in the nav. And don't forget the ent number on nodes for flags (node_flag=3). Those will definitely crash ET if incorrect.
Take a look at my byzantine waypoints for a slightly different style of a well rope climb. Key points are try to keep the bot to one side of the rope, and don't have the nodes exactly one above each other. You want a mimimal change in the x-y position so as to point the bot at the rope to prevent twirling and falling back. (See the wiki article on ladders about twirling.) The dis-mount should also be to one side only so that a bot does not try to pass through the rope (if you can go over the top even better).
3- Yes I noticed your steal action was active when the barrier was built. That will zombie just about all the allied classes. Check your aiscript control and also make sure it is active forever and goal -1.
Avoid using goal_tracker control in general but especially on maps with steals combined with other objectives (e.g can't differentiate between 3 dynamites blown or 2 dynamites blown and one steal. ) Even if you do figure a way to sequence the bot objectives so you could use the goal tracker, Humans will find a way to break the sequence and stymie the bots.
There is no button support through action_button (says so in the wiki). Mal just reserved the number for future development. Read the wiki on buttons and levers to find out how to add a floor trigger (in this case you can skip the TOI-func_constructible until you want to have the bots be aware of when the floor is open). The scripting will be a bit different but if you have trouble we can help.
If the button uses func_door and not func_button yes the bot can operate it by trying to 'pass through' it (see my 2hide waypoints re:dynamite plunger). But it is tricky and there must be a fake action behind the wall the bot is trying to reach (e.g. fake steal). I don't do RTCW so I don't know if they handle buttons (but I will add a note to the
Fritzbot ET waypointing tutorial to clarify the issue)