SDUs are recommended but not required. Also we try not to put holes in brick walls unless absolutely necessary. Plus with all of the DirecTV wiring in that area I am not surprised he didn't install an SDU.
One thing I don't like is the way he installed the ground block. I sure hope he used some grease but I doubt it since they are always in a hurry to get the job done.
Leave the splitter in place. Default login page is
and leave both user name and password blank. Make sure you change the channel frequency from auto to something else.
PS you should get rid of that gateway. Don't pay for wireless service just get a decent modem.--
I speak for myself, not my employer.