I would suggest the use of a 2-way splitter with the digital converters. The cable drop from the MATV system would be connected to the input of a 2-way splitter. One of the splitter outputs would be connected to the input of the digital converter and the other would be connected to the television tuner input. The output from the digital converter, in this case, would be the video/audio cables to an video input on the television. The viewer would select the video input to view digital broadcast television stations and Ch 2 to view the security camera.
All televisions manufactured in the last 10 years have at least 2 video/audio inputs. I would say that nearly all the tenants have at least this type of television. Where these are not available or cannot be made available for use with the splitter in the MATV cable drop, there is no choice but to use an analog pass-through digital converter.