I think you need to show us the actual error message that you got.
libtalloc.so.2 is not in /usr/lib/samba/ it is in /usr/lib/
What do you get when you run the commands
ls -hal /usr/lib/libtalloc*
ls-hal /usr/lib/samba/libtalloc*
These will show the libtalloc libraries installed on the system you are having problems with.
What do you get when you run
ldd /usr/sbin/smbd | grep libtalloc
This will show which libtalloc libraries samba is linked to and where they are located.
You do not have to disable samba before doing a backup. I never have and have not had any problem when doing a backup or a restore.
The backup does not save any of the libraries, so doing a restore will not change any of the libraries.
The more I investigate the more peculiar your error message is.
IPFire updated libtalloc in the following steps:
Core Update 173 1.3.1 to 1.3.4
Core Update 184 1.3.4 to 2.4.1
Core Update 190 2.4.1 to 2.4.2
So version 2.3.5 has never been built in IPFire.
I then went and looked in the https://www.samba.org/ftp/talloc/ directory where the libtalloc source files are stored and version 2.3.5 has never existed.