To learn more about the new Monarch, you might want to look through the playlists on YouTube.
Monarch Complete - Getting Started: https://www.youtube.com/watch?v=UD5HYh-9uyU&list=PLzBLrjkJE1LLmIDs9XC60BNyslH7qpxH3&index=2
Monarch Complete - Tips and Techniques: https://www.youtube.com/watch?v=sdeGU6ndd1U&list=PLzBLrjkJE1LIpr7-RJkzEqaTYC1RbSp81
The Data Prep Studio Help - Monarch Learning Guide has been updated as well to include the new modules, Data Prep Studio and Monarch Table Extractor (see chapters 3-5). See Chapter 24 too to learn about converting your existing text/XML models to the format used in newer versions of Monarch.
For the upgrade to Monarch Server, there are a few discussions on the Community about this that you could read through -
Hope that helps!
On the Monarch (Classic) front I doubt you will have any problem with existing V10 models converting to V14.
I guess it's possible that older models (perhaps some that were originally older than V10 before they were imported there) might have some unusual attributes but most likely they should just upgrade and work from their new depository having been converted on first use.
Alternatively use the batch update. This may be the more advisable path to take since you have the Data Pump to Automator/Server upgrade to deploy as well and the links to the newly updated .dmod files will be important for that.
Of course you should test them and compare existing and new as always when performing an upgrade. Data Prep Studio might prove to be a rather useful comparison analysis tool during that testing. (Assuming you will be receiving Monarch Complete.)
Sorry, I can't add anything about the Data Pump to V14 Server activity - it's not something I have ever been directly involved with.