Hi @Graphicus44,
There are some… strange things in your description:
@Graphicus44 wrote:
… And since I sync’d up Dropbox online (after copying my data to the new drive) the online version of my files now has those same (newer) folder modification dates. …
If no any new folder or file comes there, nothing’s gonna sync! Can you clarify, what exactly you synced at all?
You have your first question answered yourself, so what is you asking for actually?
On the second question, there is a imperfection in Dropbox application (not to say a bug) that you may benefit of. The application doesn’t sync any folder’s times/dates, except the first time when folder uploads. So, you have to clarify to yourself where the changes you talk about comes from and just avoid them. That’s it.
Good luck.
PS: If needed relax a bit, and continue after that in consistent way. 😉