Reikan park just strikes me like an ill-adviced place to stage an IRC. It's likely perfect for nations that are on allied/friendly terms with Yamatai (an Alliance Conference?), but it strikes me too much as a "look who's trying to look like the belly-button of the universe" move. I'm not really any faction leader, so, I'm not actually speaking for them... but it just strikes me that an IRC there just wouldn't be taken seriously because it'd seem so self-aggrandizing - though that means no serious progress being done in any avenues.
Pisces was borderline as a military installation, but it was close to the Yamataian border, so it kind of tenuously worked. But then, the two first turned up rather scandalously sensational. This still harms Yamataian credibility, and it's not likely other nations forgot that.
Honestly, I'd have chosen a place like Dawn Station instead. It's still semi-connected to Yamatai, but distant enough to be credibly neutral, and it's fairly well furnished. It's a competent choice that'd shows Yamatai is being sober, merans business, and respects other nations enough to stage someplace credible as neutral ground.