Yes, using CFW + SaveDataFiler to extract the saves, then SDF in GW mode to import them to the GW. Follow the "
Export Retail Card with CFW and SDF" steps here:
https://gbatemp.net/threads/tutoria...v-to-eshop-3ds-3dz-with-savedatafiler.380246/
You can ignore the parts about 4.5 encryption and needing a spare SD card (skip steps 5-7), PastaCFW negates the need for this. PastaCFW is pretty simple to install, just place the files on SD and launch from Ninjhax (using Cubic Ninja on your Sky3DS):
https://gbatemp.net/threads/pasta-c...d-on-old-and-new-3ds-required-ninjhax.388925/
Yes. Install this in GW mode and run it each time you boot GW mode and want to access the eShop:
https://gbatemp.net/threads/release-free-multi-patcher.391945/
No. You can downgrade mset though, so that you won't need Cubic Ninja/OoT to boot GW mode.