Hebrew "patch" attached - needs some layout changes as the number of keys in each row doesn't truly match the Hebrew layout. Still it is better then the builtin vkb.

I also noticed another issue and it is the "symbols" dialog that is shown when Fn+Ctrl is pressed. based on what I seen in the code (which is quite good) it can pop a similar dialog without too many changes.

The only problem I see with integrating multi-layout is the T9.
It is initialized once when the engine is set to load, so current design will only look at one file (found it: ~/.config/mcip/sysdict). This is not good and will have to only load the selected languages. I think that the T9 needs a language button as well.
the dictionary can be stored in a SQLite DB instead of a file - it will have easier access in the QML and also will not have to be stored in the memory while mcip is running in the background. For SQLite integration see here