light-locker | A simple session-locker for lightdm | Authentication library

That kind of error ("libgcc1:i386 Breaks: libgcc1 (!= 1:6.3.0-18) but 1:6.3.0-18+rpi1 is to be installed" and "libgcc1 : Breaks: libgcc1:i386 (!= 1:6.3.0-18+rpi1) but 1:6.3.0-18 is to be installed") is because multiarch support on Debian and Debian derivatives requires that all versions of a package for each architecture that you have installed must have exactly matching versions. So you can have libgcc1:i386 1:6.3.0-18 and libgcc1:armhf 1:6.3.0-18 installed together because the versions match, but not libgcc1:i386 1:6.3.0-18 and libgcc1:armhf 1:6.3.0-18+rpi1 (because the versions don't exactly match).

The problem here is that raspbian rebuilds packages, which is why they have the +rpi1 tag on the end of their version. So what you would need is either

• a repository where the raspbian versions of packages have been built for i386 -- this may well not exist
• or run pure upstream Debian rather than Raspbian -- which you likely don't want to swap to at this point
• or rebuild all the packages for i386 yourself -- which is likely painful and easy to get wrong if you don't know what you're doing.

If it's any consolation I would be somewhat uncertain about whether QEMU could usefully handle emulating a hardware-specific piece of code like a scanner driver (which is probably a plugin to CUPS or other system software) anyway.

A quick google of the scanner model name brought up this webpage: http://support.brother.com/g/b/downloadlist.aspx?c=us_ot&lang=en&prod=dcp350c_all&os=128 which includes a download for source code for the scanner driver and CUPS wrapper driver. If I were you I would try the approach of building that natively for arm.