The lender stated that because the current home will be non-owner occupied (due to secondary market rules) and a rental he can run the refi as a business purpose loan. This appears to be consumer purpose and TRID applies?
You're right in how I would apply it in my shop.
Consumer purpose because the funds will be used for the primary dwelling acquisition, even though the subject property will later switch to investment.
I would even submit that the down payment loan may be (is?) rescindable since it is still the primary residence.