One of Elkhorn's knives hits for minimal effect on the third skull. Amidor's seed flies wide.

One skull and one skull-turned-bat remain.
Matilda, Pud (helped by Tiny), Horatio, and Tiny may act next.

(Map modified from one created by AnomolousZipf on Reddit.)

Matilda looks at the skull and where its fellows no longer exist and makes an emphatic shrugging movement.

" Idiots."

Pud, feeling embolden by the sudden surge of fey magic coursing through his body, runs to the edge of the canyon and flings his magical returning dagger at the bat. In his peripheral vision he sees Titanni desperately trying to put out the flames and he casts healing word on her.

Move: move to the edge of the canyon for clear line of sight of the bat.

Action: ranged magical dagger attack with advantage from Tiny. 13 to hit for 7 damage.

Bonus Action: cast healing word on Titaani for 4 hp.

Peaugh nods and laughs sneeringly at Matilda's remark, replying in Sylvan,

Meanwhile, Pud manages to nail the flapping green bat with one of his magical daggers, with Tiny's calming reassurance. It flaps in a panic for a moment, before transforming back into a flaming skull once again.

Horatio and Tiny may act next!

Tiny looks quite proud of himself, and moves over to Gleam and does the same thing - imbuing them with magical energy to give them the help action. 

" Yes! Let them pass!", Matilda said in exasperation.

Horatio steps to the nearest flaming skull and attacks again, swinging at it with no shortage of frustration. "Stop trying to kill my friends you magical jerks! Guys, seriously, rush to the other side, I will join you once you're safe!" 

(( Attack 1: Nat 20 - total of 28, 14 base dmg + 4 dmg from Giant's Might = 18 dmg total ))

(( Attack 2: Nat 1 - total of 9, assuming a miss? ))

(( Bonus Action: Unarmed Strike - 15 to hit, 12 dmg ))

(( If the opponent was defeated from the first strike he would use whatever movement he had to advance upon the last opponent if possible to deliver the remaining blow. ))

As Tiny runs up to help Gleam, extra-large Horatio steps up to (former-bat) Flameskull #2 and proceeds to shatter it with two blows of his massive fists. The fragments flare and sparkle as they fall into the void.

The third flameskull flares up and announces loudly in Sylvan:

 It then withdraws without attacking again, slowly sinking to its previous hiding spot under the bridge.

"Oh! Thankyou, Pud!" Titaani says as she feels a surge of warm energy flow through her. Poking her head out to look for the skull, Titaani's fey spirit comes back to her side if it no longer senses danger. "Did we win?"

Evidently, you did. The remaining skull has retreated, and the way is clear. 

Everyone may act.

Ben:

”Let’s keep moving,” suggests Ben, moving cautiously forward on the bridge and looking for any other threats as he goes.

Perception:  13

Matilda is seething on the other side of the chasm, kicking dirt angrily, " Stupid skulls. Stupid little fairy miners. Dumb girl with the goofy name."

" Why is everyone here except the unicorn so dumb?"

" They could all just get together and kick the witch sisters out but instead they're sitting on their butts waiting for a old blacksmith, a fairy princess, an old man, a little girl and Pud to do it for them.....so dumb..."

Pud hobbles over the bridge with the rest of the gang, giving Tiny scritches between the ears as he passes. 

He stands beside Matilda as she vents and he joins in in the complaining.  

“What the heck was that all about?! Molliver coulda warned us about those things! 

Does anyone know what they were yelling? I didn’t understand a thing! I dunno if they were tryna kill us, scare us, test us or what!!”

Horatio crosses the bridge in silence, a simmering anger in his eyes. "I'm just going to say it. I hate the Feywild. This place sucks."

Quote from richgonehiking >>

Pud hobbles over the bridge with the rest of the gang, giving Tiny scritches between the ears as he passes. 

He stands beside Matilda as she vents and he joins in in the complaining.  

“What the heck was that all about?! Molliver coulda warned us about those things! 

Does anyone know what they were yelling? I didn’t understand a thing! I dunno if they were tryna kill us, scare us, test us or what!!”

 

" I did.  They were having fun....seems the little miners and them have an arrangement."

" Can we set up a forge here?"

Crossing peacefully over the rest of the bridge, you reach the subterranean grotto on the far side.

In the center of the grotto is a piebald pony wearing blinders. A small wooden hut is strapped to its back, and a faint clatter can be heard from inside the hut.

Molliver and her tiny companions bring up the rear. "Sorry about that. That was Weaugh, Teaugh, and Peaugh. They won't bother you again. A bit of a rite-of-passage, I guess. I admit I don't pretend to really understand brigganock culture, but you've passed their test." 

She continues, pointing at the pony's back. "That hut is the home of Obud, the oldest brigganock living in the mine. The pony's name is Keg. Obud appraises gemstones."

Ben:

Approaching the hut carefully, Ben calls out, "Obud, greetings, we come seeking your aid."

Persuasion:  26

Titaani grins bashfully at Matilda's comment about her being a fairy princess, only for her smile to fade at Horatio's comment about the Feywild. 

"Horatio, that's not fair," She says, running up to the fighter. "You're judging a whole realm by one tiny portion of it! There are some really good parts of the Feywild, this just isn't one of them."

In the meantime, Tiny rubs his head up against Pud like a cat. The giant bunny seems to have taken a real shine to the artificer, and follows him forward. 

The hut’s tiny door swings open, and a tiny, wrinkled creature hobbles into view, accompanied by a wispy bulb of light. The old brigganock peers at you through tiny spectacles and says in Common, “Big folk. How wonderful.”

Obud is old and tired, but neither too old nor too tired to show the party hospitality. He introduces himself, welcomes you to his grotto, and introduces you to Keg, his pony. "Why did you cross the chasm to see me? What can I do for you folks?"

Horatio looks at Titaani with a tired expression. "In the worst parts of the worst towns of my world you can still find a MAJORITY of people who aren't trying to lead you headlong into danger. MANY will try to steer you from it. I am sorry, but the overwhelming majority of the beings we have met here have been so unconcerned for ANYONE'S wellbeing - including their own! - that they are practically as murderous as these hags. I am swiftly losing any sympathy for these people. They deserve to be tortured by Hags, for all eternity, for all we've endured. None will lift a finger to liberate themselves, but they would enlist CHILDREN - from another realm, not even their own mind you - to die for them." His voice is calm, but his words firm and cold. "Elkhorn and Molliver are also outsiders, meaning the only folks who are actually willing to fight with us are the children of this realm, and only if already hunted by the Hags. I no longer care for freeing this place, only for getting back what was taken from you all. Once done, my vote will be to leave however we can. Let the unconcerned masses determine their own fates through their endless cowardice and apathy." 

He pauses a moment, "I'm sorry for saying these things, but will not lie. Human cities can be cruel too... But I have seen nothing like this."