>>36526882The online services for DS are offline/over.
With a 3DS and Pokebank subscription you can use your B/W/B2/W2 game to deposit through the seperate PokeTransporter (downloaded with/through Pokebank)
>>36526819*In addition to what is available in Ultra Sun/Moon you can trade online through the GTS to fill your dex or trade for a random mon through Wonder Trade.
>>36526892SMUSUM has a feature called Island Scan that allows you to get one Pokemon daily, these include several of the starters + other rare mons.
There isn't much that can't be obtained in SMUSUM and you could just look on the GTS regardless.