Somone has told me that when you perform a Panaorma Merge, only the RAW file is used and any adjustments that have been made are ignored. This makes sense except for those related to Lens correction and corormatic removal. It also does not make sense to apply these lens adjustments after the merge.
If I want to have my lens adjustments before a merge, do I have to make the adjustments, export them to DNG/TIFF, then do the merge on the DNG/TIFF versions?
You do not have to do anything like that. Lens corrections and chromatic aberration corrections are used, and so are spot removals (based on the first image). Anything else is ignored and should be done after the merge.