Quote from Mister_Whisker >>

Concentration Con save for Cultist 6: 4

And the cultist failed his Con save. The elemental and the snake are able to attack with impunity...

And they do. The air elemental hits both the cultists who blasted it and finishes them both off. Delvindra's arrow hits Cultist 6 as well, doing significant damage. Then Yasmina's bolt of force finishes him off. Cal, you can save the charge from the wand.

The first bunch of cultists have been easily dispatched, but you hear more approaching... Yasmina's familiar alerts her that it looks like another seven, but these ones are being much more cautious as they heard the commotion from the last batch... you have about two rounds to prepare if you need it.

The Air elemental servant and the Giant snake hides just by the corner, ready to attack as the next wave of cultists reach it.
Yasmina quietly conveys to the others what Al-Ashfeh reports to her. "Perhaps save your fire magic for now."  She suggests to the Tiefling before hiding again.
Lord Amir simply huffs and takes cover, impatient over not getting into the fight but understanding it is prudent to focus on maintaining control over the Air elemental servant.

Stealth checks
Air elemental: 18
Snake: 8
Yasmina: 25 (Disadvantage to notice)

(Yasmina would borrow Al-Asfeh's vision to see if she can spot the cultists preparing any sinister magic for them.)

[[ OOC: OK, first wave dispatched in 2 rounds, 2 more rounds before next wave... so the Bless spell on Zander, Yasmina and Delvindra is still active. ]]

Duwamilly quickly compliments the fellow Accursed: "Well done, kids!"

The gnome cleric is still focused on channeling the cheerful positivity of her beloved Garl Glittergold towards the party, acting as a link between the divine and human dimensions and enjoying this mystical communion.

In the meantime, the ex-preceptor already has her trusty wand ready... determined to use it to prank the enemies as soon as they show up.

Delvindra looks back and forth between Yasmina and Duwamilly in obvious conflict. Logically, she understands the risks. She wants to lay low, to draw their enemies as far into danger as possible before exposing herself to their attacks. Now that she's truly experienced life she's in no rush to die as a martyr...

But at the same time, she can't stomach the thought of leaving the seemingly fearless Gnome standing in harm's way alone.

She glances in Yasmina's direction. Hoping to convey...something. That she's not being reckless. That this isn't a death wish. That she's simply doing what she must. Because what the Half-Elf thinks matters to her.

Then, with a nod of unspoken agreement to Duwamilly, she takes her place beside the Preceptor and awaits the second wave of attackers...

While waiting for the second wave of Cultists, Duwamilly quickly jokes: "Firion must have started a Cult for visually impaired... these Cultists follow him blindly!"

Zander, hearing Duwamilly, lets a chuckle, which he finds strange in himself for doing in a situation like this. 

(I'll go ahead and assume you guys don't have anything else to do...)

You hear the sounds of people approaching, but they stop before they are in sight... perhaps they caught sight of their unfortunate predecessors.

You hear some chatter, which Al-Ashfeh relays back to Yasmina...

"Mistress... they're planning to send in creatures called 'Hounds of Judgement' ahead of them! Be wary..."

Initiative:
Cultist squad leader: 7

Cultists: 10

Hounds of Judgement: 22

Initiative

Hounds of Judgement (22)
--
Delvindra (17)
Air Elemental (16)
Duwamilly (16)
Lord Amir (13)
Zander (13)
Cal (10)
--
Cultists (10)
--
Yasmina (8)
--
Cultist Leader (7)

(I'll go ahead and give you a round to prepare for the Hounds to show up...)

"Do either of you know the mage hand cantrip," Delvindra asks Duwamilly and Yasmina, "this might be a good time to try removing some of the mummies' burial trinkets."

"Oh, unfortunately, I don't, Delvindra, honey..." Duwamilly admits, disappointed "But Al-Asfeh is invisible... He could be our living 'mage hand'!" she  chuckles.

My Echo can remove them

Yasmina again relays what Al-Asfeh has reported. She has no real opinion on whether to activate the mummies.

Cal is ready to fight the beast and changes it to the battle axe setting. 

Zander, and his echo are ready. Crossbow and Snicker are ready.

Once Zander points out that he has a way to rob (and therefore probably wake) the mummies, Duwamilly suggests that he be ready to do so as soon as the Hounds of Judgment arrive near the undead [[ OOC: Assuming he can Ready this action ]].

Other than that... ready for Wave 2 Fight!

Zander will have his Echo, which can float above the mummies, ready an action to remove the covers and awaken them. 

Okay... so, just to be clear: your plan is to steal grave goods from the mummies and hope that they attack the fiends?

I think I would articulate it "steal grave goods from the furthest set of mummies as the Hounds of Judgement are passing and hope they are both mindless enough that they attack the closest target" but, basically, yes.

(Looks at the other PCs to confirm we're on the same page)

Yes, let's try that. Especially if the echo brings stolen items to the hounds, as if he stole the goods for them.

Okay... I'm going to need someone to roll me a Deception check to make this work...

Also, yes, you can Ready your action here to steal the item as soon as the Hounds are close enough for the mummies to attack them.