[will sothis be able to use the sword of the creator?]

I think Sothis is 100% inside of Byleth's head.

[What House do you plan to join?]

Blue Lions because that's not Dimitri, that's Big Boss, and I'm joining the Diamond dogs.

[Shadows of Valentia Save Editing/Save Bank]

Here are some items I recently found as well.
 

Spoiler

Zweihander - 0E 00 00 00 5C 84 96 B6 9A 0E 85 AF
Exotic Spice -B7 00 00 00 E1 9E E7 2E 11 B4 1B 64
Steel Shield - 83 00 00 00 81 B1 57 CE 67 CC 10 6C
Iron Sword - 03 00 00 00 8A D3 8F E2 2E 1C 0C 74
Lady Blade - 0F 00 00 30 6C 45 B7 C2 FE 5E AE 1F
Dracoshield - 88 00 00 00 9A A8 38 E1 54 CE 10 72
Leathershield - 81 00 00 00 5C CB 45 C1 84 B5 9D 66
Golden Apple - CD 00 00 00 69 75 D3 2C C1 22 A8 5C
Javelin - 18 00 00 00 2D D5 F1 C1 DB 5F A0 65 
Nut of Life/Fruit of Life - CB 00 00 00 22 74 CE FF D0 0A A5 80
Ambrosia - CC 00 00 00 48 A5 A4 6D 16 E6 72 AF

 

Also correct me if I'm wrong, but it seems as if the fifth zero is an indicator to how many times the weapon has been forged, if it is one, as my Lady Blade was forged three times and the zero changed. I haven't tested it yet, but I'll update if I discover more.