"Local" means "On My Mac" - the data is on your hard drive or server, where you opt to store your "local" data, as opposed to a "cloud" source. My data is on a local server that I can put my hands on or on my laptop, depending on the account. In Outlook, the import reads as "On My Computer".
The PST files I have set up have a hierarchy of directories (or folders, if you wish?). The imports into Mac Outlook look identical to the Win Outlook export - files, given that I'm using compatible updates. Also, I'm my company owner, not the IT guy - dead simple is the way I like it, even given the 6 college degrees I've earned. Regardless of assurances by MS or Apple, after an import of data, I personally review the results of that import - I don't trust automated processes, but the import of PST files into Mac Outlook have been 100% correct. So far...
As to ensuring file mapping between multiple Macs, that's your deal to concern yourself with - I'm not being antagonistic here. I use a MBP to travel with and work in my office, and have a Mac Mini Server that hosts my files. Given what I wrote earlier here, I refer to email/attachments from archived messages often (generally for contractual reasons) - and keep a copy with one of my attorneys - but I do not "transfer" files between PCs/Macs, as I see this as a documentation (or "file check out") issue; maybe talking to your IT professional would be of help here?