You did read my orcs quick thing he said to the witch, when he was on his way through the shop and back to his blacksmiths area? If you could be an enchanter, I'd be good, however my orc is also an enchanter
The method in which he enchants is different though, he needs to create the weapons from raw material and apply the enchantment there and then, not afterwards like your witch would be able to do. So the enchanting services to not collide. But as my orc said, he's interested in greater and grand souls at some time in the future. (once he gets his business going and can afford them)
Aye, that's what got me a-thinking. Fiona herself isn't very rich - she relies entirely on her craft, and receives little more for her services as Court Mage than free food, board and the licence to research without interrogation from the Jarl. If Fiona didn't outright win the position through witchery, it was through being
very cheap that she was even considered. The Soul Gem trade could be a good source of income, a more fitting one would be enchanting herself, as she'll need someone to fill any gems she has.
It's really interesting being in the position of a Skyrim NPC
. The solution to almost all of our problems is, well, a good adventurer...