Either a team featuring an Australian, or a team from roughly the South/West quarter of the US to limit travel time.
If it's that, can rule out big names like Lakers/Warriors - probably rule out Clippers too, but I suppose a chance they see it as a good/rare international branding opportunity given how swamped they are by the Lakers. Phoenix an outsider. So maybe Sacramento, or, if I could put money on it, Utah. They've also participated in all 5 NBLxNBA trips - think they're the only team to do so?
Don't think they would go with an NBL 'all-star' team as there's no shame in a regular NBL club being beaten by an NBA side, but an NBL all-star team losing (possibly twice) to a lesser NBA team running mostly lesser players would be a bad look...
Living in London for years - the NBA pre-season games they had here (before they moved to regular season games, and then moved them to Paris) were always considered 'not really worth it' even to NBA tragics here as they charged a premium for tickets, you'd get only a few token minutes from whatever 'star' player/s, and otherwise you'd watch bench players never getting out of first gear.
Obviously this will be significantly more unique for Australian fans. Hopefully the start of something regular, but you never know, might be a one off, so def. 'worth it'.
As a Sydney guy, bummer it's not in Sydney in the NBA-sized arena there - obviously the two games would sell out in lightning speed in Sydney too - but Melbourne/Victoria will overall support it as an event much better than Sydney/NSW where there's a far more lax attitude with these things. Also with Larry K, never a doubt he would have heavily favoured Melbourne.
So, Melbourne can do a good job and heavily support it and prove the concept as worth it for the NBA, and then hopefully one day there's NBA v NBA in Australia and you could have a game in each city...