3DS system transfer to digital games 3DS question

Thought I was pretty good at using Google but could not find a real answer about system transfers.

If I buy a used 3DS that has digital games on it. Then system transfer from my 3DS (that is linked with NNID) do the eShops merge? Meaning I get those games on my eShop list. So I could then go back to my limited edition console with the digital games in tow?

Nintendo's account stuff is so weird. But I guess might allow selling digital games.

Someone please correct me if I'm wrong:

Your 3DS (source system) will overwrite all the save data in the used 3DS (target system), but you will be able to redownload those digital games from the eShop because the purchases made in both systems are combined during the transferring process. Also, make sure the target system is not linked to a Nintendo Network ID. I'm pretty sure you can't combine Nintendo Network accounts. If the target system does have the NNID of the previous owner, you can unlink it in the System Settings.