There is no list of what you can use in AI scripts. I think it is fine to use both common.j and common.ai since I've seen them used before.
However, the only person I saw use AI scripts before was AIAndy. It really depends on when it is being executed. If you need to, you can always store data in a gamecache to communicate with your map's script. (for whatever reason)
More importantly, what exactly are you trying to do with .ai scripts?
... Unless you are just trying to use AI functions in normal scripts. Then you can use native declarations (link) to use whichever ones you want. However, it is not guaranteed to work ingame. There is only a small handful of useful ai functions anyway.
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