[Pitchwife]

I've no problem with the armour - Morgoth could easily have created it as part of his fana, and as the attack on the Trees was an overt act of war against the Valar, it's not quite unfitting.
The apparent sword on Howe's painting puzzled me too, until I realized that it's actually meant to be a (somewhat shortish) spear - if you look closely, the blade is to the right, either partially obscured by Telperion or piercing its bark, and what looks like a hilt is rather a crossguard for parrying.
As for Ungoliant, I find Howe's representation acceptable, but I'd have preferred something more shadowy - a mass of darkness with disturbing suggestions of crawling legs and clusters of eyes. Monsters are always much more frightening if their precise anatomy is hinted at rather than shown in detail - cf Lovecraft's Cthulhu, who is an unnerving presence as long as he's offscreen but turns into a surrealistic pizza frutti di mare when his appearance is actually described.