Curious: Your first post lists 3 repositories with a prefix of deb-src.

You would only need deb-src if you are compiling packages.

Devuan would not exist with changes to the core of how Debian works.  Currently the number of packages involved is relatively small but will increase as Debian/Gnome continues down the rabbit hole.

deb http://auto.mirror.devuan.org/merged jessie          main
deb http://auto.mirror.devuan.org/merged jessie-updates  main
deb http://auto.mirror.devuan.org/merged jessie-security main

This is exactly what was listed in my Synaptic. Today, I repeated launching Synaptic, I did not change anything in the repositories, and tried reloading the packages list.
The problem with refreshing is not happening now, I have refreshed as expected.

Curious: Your first post lists 3 repositories with a prefix of deb-src. I am a bit unfamiliar with Debian and Devuan repository arrangements. Where could I read learn about the structure as would be explained to a noob? I once had stored some Debian repo info a bit back which tried to explain how Debian broke things down, but that education failed to fully enlighten me. Furthermore, Debian and Devuan are not exactly the same, so I anticipate differences exist or will soon come to exist.

deb http://auto.mirror.devuan.org/merged/ jessie main contrib non-free 
deb-src http://auto.mirror.devuan.org/merged/ jessie main contrib non-free 

deb http://auto.mirror.devuan.org/merged/ jessie-security main 
deb-src http://auto.mirror.devuan.org/merged/ jessie-security main  

deb http://auto.mirror.devuan.org/merged/ jessie-updates main contrib non-free 
deb-src http://auto.mirror.devuan.org/merged/ jessie-updates main contrib non-free 

In synaptic, click on settings,then repositories and you can add or remove repository choices.

Having a great experience on my Dell laptop with Jesse RC1, I dusted off my desktop box, I have reformatted and repartitioned the drive, and then I went for the big switch to Jesse 1.0.0 official.

From many lessons learned, the first thing I do after a fresh distro install is to update the packages, using Synaptic (Synaptic - such a great tool).

So, after getting Jessie installed on my eMachines AMD64X2, and seeing it boot and login and surf properly, I dropped into automatic mode and launched Synaptic.

I gave root password, and when Synaptic settled, I clicked reload to refresh the package lists.

Synaptic then gave me a blank stare, so to speak. Nothing happened. I'm posting from the same session where Synaptic was unable to update package lists, so my network is running ok. After a bit, I got this error message:

Failed to fetch http://auto.mirror.devuan.org/merged/dists/jessie/InRelease  
Failed to fetch http://auto.mirror.devuan.org/merged/dists/jessie-updates/InRelease  
Failed to fetch http://auto.mirror.devuan.org/merged/dists/jessie-security/InRelease  
Some index files failed to download. They have been ignored, or old ones used instead.

I'm guessing those repositories aren't available at the moment? Or am I in need of selecting a repository setup outside of these 3?
If the latter is the correct answer, then I'll also need some idea how to properly reconfigure the repos via synaptic.

TYVVM.