No luck

sudo apt-get install eudev=3.2.2-9 libeudev1=3.2.2-9
Reading package lists... Done
Building dependency tree       
Reading state information... Done
eudev is already the newest version (3.2.2-9).
The following package was automatically installed and is no longer required:
  python-collada
Use 'sudo apt autoremove' to remove it.
The following NEW packages will be installed:
  libeudev1
0 upgraded, 1 newly installed, 0 to remove and 0 not upgraded.
4 not fully installed or removed.
Need to get 0 B/92,3 kB of archives.
After this operation, 208 kB of additional disk space will be used.
Do you want to continue? [Y/n] 
(Reading database ... 186955 files and directories currently installed.)
Preparing to unpack .../libeudev1_3.2.2-9_amd64.deb ...
Unpacking libeudev1:amd64 (3.2.2-9) ...
dpkg: error processing archive /var/cache/apt/archives/libeudev1_3.2.2-9_amd64.deb (--unpack):
 trying to overwrite '/lib/x86_64-linux-gnu/libudev.so.1.6.3', which is also in package libudev1:amd64 220:3.2.2-devuan2.3
dpkg-deb: error: subprocess paste was killed by signal (Pipe interrotta)
Errors were encountered while processing:
 /var/cache/apt/archives/libeudev1_3.2.2-9_amd64.deb
E: Sub-process /usr/bin/dpkg returned an error code (1)

It seems that a dist-upgrade on ascii done yesterday pulls in 4.9.0-5-amd64 #1 SMP Debian 4.9.65-3+deb9u2 (2018-01-04) x86_64 GNU/Linux

as I'm on Intel as reported by dmesg

CPU0: Intel(R) Core(TM) i3-2120 CPU @ 3.30GHz (family: 0x6, model: 0x2a, stepping: 0x7)

Regards

Carlo D.

For the error, (as a future memory) you could tweak the installer and substitute the word "debian" with devuan in the proper line.

Also a little note, the scanner group is not strictly joined with the printer (The hardware device is owned as a printer) but it is related to the "scanning" chain the programs, so the various advices to check the USB port for the group "scanner" is not a real solution.

As it's time of story telling (not a Xmas story) the brother drivers are quite complicated

For the printing part a "filter" is invoked based on ghostscript that transform your image or pdf-page in sort of raw format that is processed by an executable (If I didn't remember wrong is a 32-bit) and the send to the printer in the "native" format, some problem may arise if the 32-bit library are not installed properly, the brprinter installer generally take care of this and does a quite good job.

The original "brprinter-install" script was developed in a french forum and the adopted by brother.

The part that install the library in the wrong place is this installer and it is not well updated (the product is out of production so maybe it will be unmantained).

The scanner part is based on sane and you have to take care of the presence of the line brother3 in the /etc/sane.d/dll.conf (generally is the last line as it is added by the installer), so if in future the scanner is not working anymore maybe an update to the sane package replace this file.

Some decision made in the installer are not update proof, the relevant part as the drivers are generally safe as they are not overwritten, but the /etc/sane.d/dll.conf and the part of the /udev rule are somewhat fragile, and have to be the first part to check when a problem arise.