I don't think BA care much about 3x3, or they would have sent the Aussie team to more of the recent tournaments to get points. We have attended 2 when other teams have gone to 8 or more. At the moment the Aussie team is not even certain to make the olympic qualifying tournament given their poor world ranking (solely due to not playing in enough points-earning tournaments). Also, the 3x3 team don't even have a name (i.e. Opals, Gems), nor do they have a dedicated page on the BA website.
Besides, there are no 3x3 events that clash with the Asia Cup, so there is no reason Cole and/or Garrick could not have been selected to give them some Opals experience.
If the 3x3 team don't make the Olympics (a good bet given their small odds of making the qualifying tournie then actually winning a spot), then surely it will be too late to for Garrick and Cole to have a shot at making the Opals. They won't have been to any camps, played in any games with the other players, know any of the plays, nor had much exposure with the coaches. These 2 would be way behind any other guards.