So Mozzi will only compile on 1.0.5. So if you are still going for the Mozzi version, you are going to have to stay on that. reference. Just the first error is odd, because the library is DAC_MCP49xx, not DAC_MCP49x1. Perhaps try downloading it again? The download is weird, because the .ino file you get is actually a .html file you have to open to view the real .ino file (rename the original .ino to .html) on the github last I checked.
I find working with the digipots way easier than ever trying to get Mozzi to work properly. If you are dead set on it, that is ok, there are many things released that use Mozzi.
If you still have no luck, try the digipot version, and if that still doesn’t work try either mine or someone else’s firmware. Mine will compile with no extra downloaded libraries on the newest version of Arduino, and is also completely standalone once installed.