I’m a week late but the issue is Haze is essentially at a 100% pick rate while Ivy and Kelvin are among the least popular - hence why you never get Haze. You need to pick two equally popular heroes - like Infernus and Pocket for example - to put at white and then Haze on purple. That’s the only way to force it. But expect longer queues.
The SoD expansion was made by Beamdog some 15 years after BG1 was released. It’s admirable that they tried getting the original voice actors back, but otherwise the team behind BG 1&2 (and ToB) had nothing to do with it. I couldn’t get through it, and I have a hard time supporting the Enhanced Editions as is due to Beamdog inserting their fanfiction into them as well - though I recognise they’ve been instrumental in revamping the engine and bringing the games to a new generation of people.