Yeesh, people! I go to my other job for a couple of days, and look what happens! All right, let's start where I left off:
Skyfire:
-"Why does it mention skimmers?" Because it can only take Snap Shots at the targets not listed, and they wanted it to shoot normally at Hovering flyers.
Flakk missiles:
-"No really, why can't I take them?" They're not in your codex, and not in your FAQ. The same reason why Codex: Space Marines can't take Stormravens. Flakk missiles are an upgrade to missile launchers that has yet to appear in a codex. That may change in the future, but right now, the upgrade is not available.
Daemon Weapons:
-"Are daemon weapons unusual power weapons, per the rules?" As I said in my first response, yes. They don't get the normal weapon type bonuses, just AP 3 and the abilities listed in their codex.
Dual Power Fists:
-"+1 to Attack?" Yep, just like 5th edition. Hulk hands!
Power of the Machine Spirit:
-"Can the Machine Spirit fire an Interceptor shot while the rest of the vehicle fires with Skyfire shots?" Nope. Power of the Machine Spirit does what it says it does, and no more. You pick your firing mode and stick with it.
-"Can the Machine Spirit fire a third missile?" Good question. As currently written, yes, unless an FAQ says otherwise.
-"What about superheavy flyers?" They're not in the rulebook. Wait for 6e Apocalypse.
Allies:
-"Can I take Coteaz as an ally?" Yes, but he can't join your squads.
Power Weapons:
-"Can I model whatever kind of power weapon I want on my guy?" A model can be equipped with whatever options it came with, per the package. Slapping axes on Death Cult Assassins is modeling for advantage, and the models would be removed at any tournament I'm judging.
-"But if that's true, wouldn't you have to have searchlights on your vehicles, and paint your Ork vehicles red?" WYSIWYG is still a thing, as far as I'm concerned. So, yeah, same as always.
-"Can I use a Necromunda model that has the wargear options I want?" That's a bit trickier. I'm thinking not, for the same reason that you couldn't grab a power weapon you like from a Death Company sprue and throw it on one of your Bloodclaws. If we're restricting people to what the official model for that unit has, then we're doing it across the board.
Flamers:
-"Does a flamer using the Wall of Death rule have to worry about placing the template over allies?" No, because the template is never placed. Indeed, the enemy unit doesn't even have to be within range; Wall of Death Overwatch attacks are an exception to the usual rules for line of sight and range.
Whew!