I think this is all pretty well grasping at explanations at this point; the actual proof we have, and all canon evidence, point to Shards being the soul(heh) source of a Fullbringer's abilities.
Hell, the fact that their Shard can be stolen and then they lose all their Fullbring powers is proof of that! How on Earth can anybody even begin to deny how simplistic the logic is there? Losing the Shard=Losing their Fullbring; if they had obtained 'their own unique power' it wouldn't disappear with the Shard's removal.
The abilities get added to the profile, The Visionary is a 'Likely', and Schrift abilities are a 'Possibly' with a key indicating The Almighty allows for power bestowal to one's self, all things that are supported heavily by canon proof and require theorizing to even begin to dismiss.
I do believe we have entertained all argumentation long enough to postpone creating this profile properly, yes?