Noooo not at all, he doesn’t lack anything, nobody needs an enn, that comes from the religion of demonolatry, so it’s the wrong method for the wrong current. Only a scant few entities that Demonolaters have very recently created enns for have them, and you will find those in books they have published. So far the technique works well enough, but I feel that’s thanks to the practitioner not the technique.
Don’t go worshiping Ant’harratu, that might just annoy him; he’s Azazel’s man and he expects you to stand strong as an equal spirit. None of this “submission is strength” cop out, gratitude yes, groveling no. The meek do not inherit the earth: they are lunch. 
Yes that’s correct. 
It’s very super easy Sigil magick, I know I’ve posted his sigil here before but here it is again. Might want to check the spelling. In my copy it’s on page 128.
You can just use his sigil. Here’s how: