Not true.
I just did some brief tests to make sure, and cloaks do indeed provide more resistance the higher they are enchanted much like how stat boosting armor pieces grant more points the more enchanted they are.

As an example with nothing but a leather cloak of fire resistance on you can step on a landmine and take thereabouts of 30 total HP damage from it. A cloak of fire resistance +5 will reduce this to about 10 damage.

I think that's more to show that they're incredibly stupid rather than mindless.
Some of the tougher kobolds can actually be seen with ESP though (Rondol being one)

Gibberlings are also quite stupid it appears.

I dunno about "bug" say, but that is definitely a good point. Monsters raised by necromancy serve their resurrectors unquestioningly and mindlessly so it'd make sense for them to lose their "intelligent" status.
Also presumably the brain is dead.

There's mention of them in the old documents, but they never got implemented and IIRC there's no references to them in the source code itself.
I imagine the tentacle limbs would be granted by mutation effects and/or God prayers (e.g. something Scabies would do) and would have higher DEX/AGI at the expense of lower ASTR/LSTR. Perhaps classed as whips for unarmed attacks.

Good question. Maybe at least one per alignment?
I can bullshit up some explanations for most of the gods being able to help, perhaps some gods would be better for it than others:

Valpurus: No action.
Legifer: Makes you explode violently with the power of the explosion being based on how raging the fires are on your person. (Extinguishes, and no damage to yourself)
Atavus: No action, since he's unique among the gods in how he acts.
Dulcis: No idea.
Seges: No action - not sure how a god of nutrition could help. Maybe removing the fat from your body so you don't burn as fast, at the expense of hunger.
Sophos: Teleports off and replaces burning limbs
Silva: Briefly encases you in rock / smothers the flames with vines, forcing you to stay still for a few turns.
Mellis: "Trades" your fire for smoke/air/skunk smell/something else.
Loricatus: Strikes you while the iron is hot, extinguishing the flame but hurting you a buttload. Might increase END very rarely?
Cleptia: Slows the item so it takes longer to burn through your stuff
Nefas: Spills vomit or vodka (!!!) over you to extinguish the flames. (Could cause rapid rusting, acid burns, or in the case of vodka, explosions)
Scabies: Douses you with poison. (Poisons you)
Infuscor: Outright removes the flames via magic / teleports the affected items off you.
Cruentus: Dunks the player in blood/acidous blood. (Rust/acid burns)
Mortifer: No action.

I SWEAR there was some kind of pre-defined script somewhere that made our invisible golem friend appear in UT4.
Maybe it was in a specific variant, or a line somewhere in the source code?

EDIT: On closer inspection it might have something to do with the fact that UT4 has a base difficulty of 100. For comparison, Oree's Lair has a base difficulty of 90.
In addition it has a difficultyDelta of 0, meaning that UT4's difficulty is always 100. Or, it should. I can't find where either of those entries are referenced elsewhere in the source.

Rings of searching are made of oak wood, so it makes sense that they'd catch fire.

On a semi-related note can we make a change so you can now dip anything into liquids? It'd be much more convenient than say, smashing a bottle of water over myself to wash off assassin blood.
...or does our new update let you do that now?

Really the encourager should be gaining massive LSTR but I guess something's put in place to stop that.

I wrote a section on exact nutrition calculations over on the wiki, under "Eating"

We must go wider!

Yeah seems fine to me, it's not like there needs to be space for links or whatever around the sides.