Agree with inkahauts - need more information. And want to really emphasize the comment about going wired as opposed to wireless.
It does sound like part of what you want to do is integrate DirecTV with other sources, mainly streaming sources, so identifying what all choices you want at each viewing position needs to be part of your overall description.
You will get a lot of input here, suggestions will be plentiful, and you will hear a variety of positions/opinions.
As far as DirecTV based equipment is concerned (which would just be a piece of your overall system), you can get one Genie which can serve a local TV and up to 3 other locations simultaneously, and up to 8 other locations total (but only 3 at a time) using mini clients. You can supplement that with either regular receivers or regular DVRs to get to your total 12 locations. If all 12 TVs need to do DirecTV simultaneously and independently, then you will need a Genie, 3 clients, and 8 other receivers or DVRs. One other consideration is if you want 4K capability - that will be limited to a maximum of 3 TV locations with DirecTV (you have to use a C61K client off an HR54 Genie to get 4K).