I haven't installed Catalina yet, but I've as good as set sail for the islands. I'll probably be installing next week sometime. Although I hear of mail issues so I am a little concerned about that.
Of the things that I outlined earlier…
I have migrated the settings for all the FTP / AWS Severs that I need to access from Yummy FTP to Transmit. No product had an import for the Yummy Bookmarks (which to be honest looked encrypted) so I had to do the old copy and paste routine. Still its done. I could have gone with Cyberduck or ForkLift but I'm a fan of Panic (I use Coda) so I'll go with their product.
I downloaded the latest versions of the Cannon DSLR Utilities. I rarely use them, but handy to have around.
I downloaded the latest EPSON Print Drivers and Utilities. I should come with the Catalina install but no harm in getting them early. The Cannon ones are apparently included in Catalina as Cannon doesn't provide them online for downloading.
Turns out my MySQL DB Inspection and Query Tool is compatible so that is good. I would hate to have to resort to the junk that is MySQL Workbench.
I found a couple of free programmers file editors that allow you to display and edit the contents as HEX or ASCII. One of them will work for sure.
Other 32-bit software
Everything else that was 32-bit got archived off to an external drive for reference. If needed I can grab them back and run up Mojave. Mainly I kept them so that I know the names of the utilities to go find a 64-bit version of should I need them.
The year long project to move 20 years of POP3 E-Mail to a new IMAP server is almost complete. Earlier I moved everything from 2011 - 2019 and that left 2000-2010. As I type the last ~2000 messages are being moved. Once done I use AppleMail for work e-mail, PostBox for the last 2-3 years of personal e-mail and Outlook for everything in archive (1997 onwards).
There is however the minor issue that all of 2002 seems to be missing. Everything sent, everything received. I have a backup somewhere that should have that data - I hope.
My backup software (Arq, ArqCloudBackup) will work just fine. Time Machine I assume will work just fine. SuperDuper is the problem one that I am waiting on.
I will install a copy of Mojave either on a spare partition or a USB stick so if needed I can boot up in Mojave to run that application that I don't have a good replacement for.
I think that that is everything. Next week I'll take an image backup of my boot drive using SuperDuper and hit install.
Hopefully I'll have a smooth landing in Catalina.