I know about the esp limit for Skyrim and I have also read some stuff indicating that there is a limit to the total number of all types of files that can be in the Skyrim/Data folder. Is there any truth to this limit and what might that limit be? Thanks!

I'm fairly confident that there really is no limit to the total number of files that can be in the Skyrim/Data folder. Mine currently contains 3,039 files within 278 folders. That is "slimmed down" quite a bit from my all-time high of 11,657 files within 287 folders. That second set of numbers came from a mod testing session about a year ago, which I had just over 200 mods running. (Currently running only 27 mods)

Oblivion has a limit on the total number of esp files (including both active and inactive files) that could be in the data folder. That limit was 400 and mods like Wrye Bash (with its ghosting feature) and OBSE plugin Trifle solved this issue. But Skyrim has no such issue.

Wrye Bash has been complaining that it can't perform ghosting because there are too many files in the Skyrim/Data folder. Kind of ironic.