Is it structurally ok to have wooden support for the concrete or brick? Something tells me that wood is changing its dimensions in time, and this can cause cracks.
The concrete slab you cut on half to make way for doors could be built there for structural integrity of the house. Looks like it's at the same hight as the concrete crown that goes around the whole perimeter of the building and it was holding the walls from bending outward and roof collapsing in. It might look like overkill for places like UK or Latvia, but Balkans is a seismic zone and building requirements are different there. Anyway in your situation most likely the worst that could happen is some vertical cracks above your doors and inability to later legalize the reconstruction if you decide to sell it.
