1. add users and groups and force them to the same uid

2. copy /home/*

3. find a list of installed packages and install them anew

Yes, that will work.

1. Be aware that some system users might get different uid/gid. That might be an issue if you're doing stuff over the local network. (I ran into this with geneweb.) It might depend on the order that some apps are installed.

2. I usually copy my home files last, and sometimes I just mount the old partition and symlink to the old home.
It's usually better not to copy your old desktop configs. Some things may have changed.

3. 'dpkg -l' will give you a list of all installed packages. You don't need to install all of them, as most will be installed automatically with others. In some cases, package names have changed. 'apt-cache search' or 'aptitude search' for partial names will help.

I want to install Devuan on a new shiny 3 gByte disk, keeping the old wheezy disk for backup.

This is the plan:

1. add users and groups and force them to the same uid

2. copy /home/*

3. find a list of installed packages and install them anew

Is this viable?

Alternatively  I could copy the old disk verbatim and upgrade, but that means that maybe some bitrot copies over too.
If I report problems with devuan, that must not be old problems, so I don't like that option.
(Problems I currently have:
   editors don't work in trn
  hack doesn't save properly
)

Groetjes Albert