I have a clarificatory question. So now I finally get what connectivity methods ensure a truly responsive Avenue (GTS Nego is one of them) and so I want to ask, since I already recruited my friend (who has Black2 and he now runs my Dojo) but we only connected via GTS so I don't have his activities and stuff like that. If I encounter him on GTS Nego, will his shop be automatically updated with the information, or will I have to build over his shop so I can recruit him again later?
It will be automatically updated.
I did it with my own Black, when I changed my trainer class and trade again with my B2, the shopkeeper's sprite gets updated.