I ahven't seen this ANYWHERE near as bad with the newer versions of LO. STill not perfect, but definitely usable even with shared documents. This issue is actually the reason I have a 6-seat license for Softmaker Office Linux, since I needed interoperability with M$ Office formats for work with my old job.

Many years ago the legal profession, in the U.S., adopted ms-word. Two attorneys I know, who are both "power users" of ms-word, have said there are compatibility problems between different versions of ms-word and they have both said, in their opinions, mickeysoft does this on purpose in an effort to "encourage" people to buy the latest version of ms-word/office.
You can save a document as a .pdf file and send it along. At that point it doesn't matter what software was used to create the document.

MS have historically changed their file formats between versions to hamper compatibility with other similar programmes, but I don't think this goes on much these days. The old word doc and xls formats were binary, whereas (as I have already pointed out) the newer formats are mostly plain text xml.

I understand and agree with all your collective statements in this thread about why this is a stupid idea, I should use MS Windows if I want to use MS Office, LibreOffice is just fine, etc. I LIKE LibreOffice. But I'm between a rock and a hard place.

I'm disabled & retired (w/no financial resources, living only on Social Security, etc.), no longer have a Windows PC and only have a Linux box because someone gave it to me. I can no longer work in my lucrative, 30-year career so to earn some extra income, I want to try being a general transcriptionist. Trouble is the only audio/visual player that has the features I need is incompatible with LibreOffice Writer.

The AV software I need to use is Express Scribe, which runs fine using Wine. It allows you to redefine keyboard function keys for AV control - so you can keep your hands on the keyboard. Those f-key definitions will override -MS WORD's- while the AV file is playing so, again, you can keep your hands on the keyboard. Typing speed is paramount. But LibreOffice Writer isn't compatible with Express Scribe. (I've seen web pages for supposed Linux substitute software for Express Scribe but they don't work.)

I can't afford another computer so IF I'm to earn money as a transcriptionist - and it seems like the only viable option right now - I NEED to have MS Office (I still have the 2003 CDs) running in my Linux Mint environment - as offensive as that is to some of you. I've found all sorts of web pages for how to install it there but no joy. I would REALLY appreciate some help here.

Use a Virtual Machine, like VirtualBox (www.virtualbox.org), install Windows 7 in that and MS-Office 20xx again in that Windows VM.

But you should pay for that Windows licence & possibly another licence for that ms-word and possibly another licence for that AV software etc...

As he said he had the CD-rom's the OP likely already got a license.