It sounds like you perceive - or are afraid Tanya will perceive -the changes in the job function as criticism of the way she was doing her job before. But apparently that is not the case - it sounds like a lot of new tasks and responsibilities have been added to the job.
I think you should carefully consider what parts of your list are duties/policies driven by what needs to be done, vs. processes/methods that you prefer, have developed, or work best for you.
The new duties/policies of the organization as a whole, and specific tasks/deliverables that will be expected of her, are what Tanya needs to learn. Your own method of getting it done is optional. To use an example from my own job, when I took it over the outgoing person spent a LOT of time showing me her detailed notes of all the instructions Boss gave her on a daily basis, cataloging where she kept individual files, and a history of various changes to client information. She spent very little time training me on the required procedures to get things processed through accounting, requesting library documents, and using the specialized in-house software. That was really backwards.
I think if you keep it task-oriented rather than process-oriented, there will be little opportunity for Tanya to feel criticized. She will have ample time to adapt her own work process to the new requirements.
