It would seem that after I delete all of the old formats out of a document, including paragraph, character, and table formats, that I do not have a fully corrected version of the FM file after importing the new template. How can I ensure that all of the old formats are replaced by the new format? Is there a clean way to apply a new template without copying and pasting the old content into a new file with the correct formats?
Secondly, how can I make the default bullet building block larger as in a larger dot?
Oh, I'm using FM 17 - still not sure about moving to FM 19.
IIRC all formats are additive unless they are the same name as the ones they are replacing. The easiest way is to use the Import function to just bring over what you want (paragraph tags, character tags, variables, etc.)
You can, in effect, "empty" the catalogs, but that only really thoroughly deletes those formats not used by any content.
Any content that was tagged is still there, and still carrying those formats, which are now merely non-catalog formats.
I have no fond memories of having to clean up old documents carrying generations of various formats of different (often obtuse) names, but all serving the same role. Delete all. Utilities > Create And Apply. Save as MIF. Search and replace with current names in a text editor. There are likely nicer tools for this now.
Welcome back. It's been a while!
My approach is to use Alt+d (I just hold it down in any of the Delete Formats From Catalog until all of the formats are gone), then import the new formats/styles. The ones with the same names will match up. Then try Bob's suggest of Create and Apply to draw out the paragraphs using styles that weren't in the template you just imported from. Retag and remove. Remember that you can also use Find/Change to find overrides and remove them, which is useful at this point in your documentation.
As for the bullets, you need a character style. I wrote this up for a student years ago, but it still works: https://www.rockymountaintraining.com/adobe-framemaker-but-i-dont-want-a-plain-round-bullet/. To this day I don't know why I chose a squirrel bullet in the example. Please ignore the squirrel and the font change—just make a character style for the new larger size and assign it through the Paragraph Designer as shown.
If you have to do this for a lot of files, I'd suggest getting Rick Quatro's FindChangeFormatsBatch plugin. You can use it to create a table with all the formats in use listed and pair them with the new names you want, and then running the script will rename everything for you in an entire book. It'll also delete the old formats from the document. I've been making extensive use of it as I redesign the templates at work. He has another plugin for deleting formats that is also useful for getting rid of unused master pages or reference pages.
+1 to linsims suggestion, the FindChangeFormatsBatch plugin is a great tool for that purpose. You can easily map all name variations of paragraph formats to the same target paragraph format and get rid of all unwanted versions at once. Afterwards you could re-import the current set of paragraph and character formats into the same document for clearing any leftover format overrides.