So Im starting a 40k army, and I have chosen to run an Iron warriors army, about 7 years ago I attempted to run an Iron warriors army back when there was more of an option to have an army like that and it would have its own rules set in the codex, but ofcourse I only bought what looked cool and totally didnt make it an iron warriors army, I eventually quit for a long time, but since last year Ive gotten back into the hobby except I was playing only WFB which I really enjoyed. but now Im ready to go back into 40k again thanks to wanting another shot at Iron warriors (not to mention all the peer pressure from friends ).

Now after that bit of backround here are my questions

Is there actually a Dark adeptus mechanicum that chaos acquire their tech from? cuz it'd be cool to have a couple techpriest models in my army (Ive read the book "Dark adeptus" before, so Im curious)

and with everything in the new chaos codex being so generalized, which codex would provide a better rule set to represent an Iron Warriors army? Codex: space marines? or Codex: Chaos space marines? (I have both, along with the old chaos codex as well)

and the last question is, if anybody knows of any good homebrew Iron warriors rules for 5th ed. rolling around on the net?