After sleeping on it and reading the feedback from @matt I have removed the ORIGIN and CALLER stuff. I added a note in the rationale saying that ORIGIN and CALLER should be the same for the first frame of the transaction for all transaction types, and that if future transaction types want to include additional data they will need a new opcode.
I am mildly convinced that allowing differentiation by transaction type may lead to some bad things like contracts not working for people who utilize certain types of transactions, but in that case I’m not sure how to best deal with sponsored transactions. I’ll continue the discussion on that over in EIP-2711: Separate gas payer from msg.sender