Open FBI 2.0.5+, select the "SD" option, enter the folder with the tickets, then press Y and "install all tickets" (you can also select individual ones with A instead, but if you only want some tickets there are more appropriate tools than TIKDevil)
Since FBI 2.1.0, you can also run the dowload directly from FBI. The advantage compared to eShop is support for foreign and delisted titles, the disadvantage is not downloading a seed for 9.6+ software.
Yes, but like cia installation, they may be removed when the eShop is accessed (in-app or via the full software)!
No, wings.json is a format used by CIAngel that includes title names for searchability; since the current version TIKDevil is strictly aimed at mass ticket generation, it just uses enctitlekeys.bin!