@jtth I believe you can, but not with a console command. Here is why...
When a console command is called, it reads and runs a small script. Now, depending on what you type, it will run a different script... For example...
Cheats:DrizztDefends()
(Was in original BG:TotSC)
It runs a script that spawns drizzt in his normal state. But it cannot run any script not preloaded into the game.
However, not all is hopeless.
If you have DLTCEP and EEKeeper, I believe you can load your save game, and save neera as a cre. Load the cre into DLTCEP, go to the spells tab, and click memorize all spells. Then override the previously made cre.
If you open the creature browser in EEKeeper, the file should appear. I dunno if there is a way to add it into your party, but you can override the normal neera meeting.
Anyways, good luck! I don't think my method is the best, and using EEKeeper might be easier for some (but I hate clicking my mouse for 2 hours... It drives me nuts), but if you don't feel up to it, I suppose you don't have to do it this way.
Thank you for your time.