Cheating for the 3 saber parts won’t work , the game gets confused thinking the quest was never completed, just play the game normally acquire all 3 parts and a few usm crystals then with bao build your first usm.
After this your other npc’s can build their hilts, once the other factors are reached, properly completing the saber making quest and having them trained as force users..
Once vias has recovered and you talk with her , take her off the ship to build her hilt , at least I did and it works fine.
The dlg option is “there is something we need to talk about” , or the bottom reply *
For Atton and Boa I think you have to take them off the ship to build their hilts
Again The dlg option is "there is something we need to talk about" , or the bottom reply .
As for bandon ‘s .. it’s hiding and I would appreciate those that have found it. To not spoil the surprise for the others. It’s my personal Easter egg in the mod.