Solar's Harper

Your blood cools, and mind and body are reunited under your control. Your will had faltered, and the essence of Bhaal was there to take advantage.

If that's the one you mean, Agashi, then that's fine according to the file in reference (Player1.dlg), all she would need to be is valid to speak.  Other instances however ping her RomanceActive status before setting another variable, such as the one that endangers them.  Headache inducing to say the least.

Setting RomanceActive to 3 (broken up) might also work, 0 tends to be the non-existent number that will allow the romance to initiate (1) should the Match variable also be true.  Or perhaps changing the variable that says your PC is a match.  Pretty sure a simple check in the code to verify which state it is or isn't might be the fastest solution in future situations, not my call to make.  Aerie Globals to keep in mind:

Global("AerieMatch","GLOBAL",1)  - Her romance is utterly dependant on this early on, being the first global it pings to see if the next talk can be had.

Global("AerieRomanceActive","GLOBAL",1)  - Reading the files, this is set after telling her competition to butt out and admitting interest, so for all intents and purposes RomanceActive doesn't really exist until then.

Global("AerieRomanceActive","GLOBAL",2)  - Consummation.  Or something along those lines, this IS Aerie after all.

SetGlobal("AerieRomanceActive","GLOBAL",3)

See if that helps.

Probably sounds rather inane to say it, but does it truly matter? The BG series has a tendency to leave large gaps of "fill it yourselves" in its logic, one reason why there's so much content out there now I suppose.  Heck, even that novel spin was an attempt at that; it's there, it's a thing.  Same are the millions of fan fictions which could arguably be seen as the true story, only the original author of this whole franchise could reasonably claim otherwise.

Not an attempt to whittle this idea bubble into nothingness, mind you.  Just not sure what it really adds beyond what already exists, doubly so for the mage PC - rats, who needs assassins or incompetent thugs when the rats will get you, hm?

Then again if they're anything like Bethesda's Dishonored's rats, then we have a problem.