So I’m making a Magic Item I’ve called Twilights Arsenal, it’s an item that makes 4 weapons of your choice orbit/float around you. I got the idea from the Anime Overlord form the Platinum Dragon Lord (Riku) 

so one of the things in this magic item is that you can use your Spellcasting modifier instead of your strength modifier for weapon attack rolls with the weapon, and I was wondering if there’s a way for me to add that so it appears on the Character Sheet?

A homebrew feature cannot "add" weapons or replace weapon stats the way you describe.

Items cannot add actions either. 

Basically, what you want to do cannot be done as a magic item.

Welp, that sucks, but thanks anyway