Can dialogue have as condition that it takes place in a particular cell, and can it have as condition the NPC's current AI Package?

I believe both are possible, though I've only done the latter indirectly. I set a quest variable in OnPackageStart or OnPackageChange blocks and tested that instead, both for legibility and because I was using the same result in a lot of other things. The GetCurrentAI functions aren't always specific enough, so you may need to do the same.

GetInCell is used in a lot of Beth's dialogs. I think it's the main use of the "dummy" cells.

Using a particular cell as dialog condition works excellent.

I'm trying to recall it it was Current AI-package or Current AI-procedure that did not work well at all, simply because the AI-package returned would always "In Dialog".

I *think* that currentAIpackage worked correctly in dialog and currentAI-procedure returnedthe number for "In dialog" - at least that sounds most logical. (I used another workaround so I cannot find the answer in the mod anymore).

However, if it doesn't work correctly, this is the reason.