Bank and Transporter update is out guys :]You get a Mewnium Z for updating.
Transporter update allows you to transfer mons off of RBY VC,
but Mews obtained with the Mew glitch and any glitch pokemon such as Missingno. are not allowed to transfer (I tried...). Someone has reported that transporting a box with a Missingno. in it may alter the names of your mons in the box to MISSINGNO- or take on the name of the pokemon before it (only 1 case so far), so be careful. All mons from RBY have their HA and may have fixed natures according to their levels.
If you can't find the update, type in "bank" in the search bar in the eShop. You can't use Pokemon Bank until you apply the update.
There's a national dex option in Pokemon Bank; you can access it by pressing Y. You can also view records such as # of eggs hatched and pokemon encountered total between games.
I haven't transferred my living dex yet myself, but I will once I get things organized. Transferring anything from XYORAS to SunMoon is a one way trip, they can never go back to XYORAS even if they have nothing from Alola in their data.
Also not transferring right away because...