(Sure, thanks! :)  Anyone need chain mail?  Otherwise Choir will dump hers, she's over her carrying limit.)

Done.

Choir probably could have also raided another of the guards for some plate armor.

(Hmmm, I guess I could, if that was okay with the DM. )

On the way to the abandoned mansion, Polly take out the potion she found on the ghouls and try to discern what it is inside. 

She will ask Fran about it since she is their go-to person with this kind of things. 

Ooc: do I roll an int check or an arcana check for this? And can I do it with advantage if Fran helps Polly out? :P

Since no one in your group is an alchemist, I say Polly goes with Identify, as usual.

And since dead guards are around - Choir might as well replace her armour. Survivability first!

She just puts it back into her pack after a while, until they have time for a safe ritual. 

Just saying: 
"The identify spell is the fastest way to reveal an item’s properties. Alternatively, a character can focus on one magic item during a short rest, while being in physical contact with the item. At the end of the rest, the character learns the item’s properties, as well as how to use them. Potions are an exception; a little taste is enough to tell the taster what the potion does." (DMG p.136)

So are we agreed that we are taking a long rest?

(In this case - identify. You can guess the magical property of the weapon, if you are familiar with this kind, but if you never tasted/brewed one, do not know and can not recognize the ingredients of the portion, what good would it do to taste it? Identify!)

Fair enough. :)

The group slowly approached the mansion (fortunately, unchallenged). It does not mean devils are not watching, but not one showed up. The building used to be surrounded by trees. Most of them are burned by lightnings by now (the scene made druid weep), but they played their role and protected the estate to some degree. It is big enough to accommodate dozens of people that came here with you.

Survivors (those who were not completely exhausted), without complains went on with the turning the building into a more permanent habitat: some checked and barricaded the windows, some went to the cellar in search of food drinks (water was carefully measured and stored), others were turning rooms into sleeping places. The mansion now resembled a castle under the siege and soon begun to give that feeling of safety - ephemeral in Avernus, but the more precious because of it. 

Choir will begin looking around the mansion for evidence of what gods may protect it, and will give them a little shout-out when she does her prayer to Akadi before resting. And also, keeping an eye out for anything else of interest. (Investigation 10)

Polly will look around the mansion and try to find an unoccupied room where she and her friends can bunk for the night. If she finds a suitable place she will proceed with identifying the potion. 

After that she will start to create the magical dome and have it blend in into the room. And also allow access to the others. Then, exhausted from the day she will drift asleep. 

There is nothing special about this mansion - it is (was) a house of a rich man, who like spacious rooms and gilded wall decorations. He was not particularly religious, it seems, and thought Choir's prayers were granted, kenku could not help it but feel pulled away from her goddess, like a child watching his parent though the closed window.

The potion, Polly was investigating, turned to be the potion of invisibility. In that room, where all the heroes (minus Lulu, who staid with the children for the night) gathered and that Polly covered with the dome, everyone could sleep relatively safe and sound tonight.

The mornings here did not differ from the nights in any way, but elturelians, used to live in the City of Two Suns, knew how to sleep with the lights on (and Ordrag could enjoy the opportunity to learn that trait).

Considering that his last sleep was in Candlekeep, which felt like an eternity ago, Ordrag could easily fall asleep no matter how bright it was.

Before going to sleep, Adray met with some of the other civilians that they had rescued and brought to the mansion.  Specifically, in regards to setting up to alert everyone to the devils or other monsters that may approach.  After which, he took first watch before going to rest with the others in the sphere.

As everyone settled into the mansion, Fran would finally be able to take a moment to review her set up. The battle smith will meticulously tend to her loyal defender, mending and resetting his repair gears for the next day. Once she was satisfied with Brutus’ tune up, she’d instruct him to go below and help keep the kids company with their guardian. Then she’d move on to her next project.

The artificer would be shaking her head at herself realizing she had left some infusions go unfinished and unattached. Perhaps she was a little distracted by the bit of attention she received back at the flaming fists that she never finished her work. Therefore she’d spend her evening ensuring she had everything right before bedding down for the night in Polly’s cozy corner of the mansion. She was thankful for their mages arcane comfort.

Adray gets to some light stretching in the morning and then through some of his battle stances and forms.  When the rest seem to be getting up he gathers them up.  "Unsurprisingly, lets expect some hard battles today.  We need to go to investigate the graveyard and see if the Grand Duke is still alive."  

He begins to pace.  "Its a graveyard so probably undead.  We are in hell so likely more devils.  Casters.  Take what time you can to prepare.  I'll make us a quick bite and we can head out."

In the morning, Choir makes her prayers for spells that will serve the purpose of facing undead and saving a lost Duke. Perhaps if they can win the trust of the people here, Pherria will be more reasonable when Choir attempts to talk her out of the book.

Fran would have probably slept the best she’s slept in a while. She’d take her time to get up in the morning, moaning and groaning as she’d stretch her body aches out. Truthfully though, she had nothing to complain about compared to those who actually took hits from battles.

The artificer would take her place against a wall, arms crossed. She’d nod along to Adray’s summary and suggestions. Making some mental notes, she’d make sure to double check her supplies and of course pounce on his generous offer of preparing them a meal. Fran wasn’t going to say no to that!

Ordrag prepares for undead or devils the same as he does for cultists. The silvered longsword seems to have held its edge perfectly and only needed wiping, and the warhammer he received from Choir also requires (re-Choirs, haha) little maintenance beyond cleaning. The half-orc instead spends some time bashing the dents out of the breastplate and greaves he salvaged from the High Hall and adjusting the straps and padding to cover his bulk. He also pays some curious attention to Choir at her prayers, having not witnessed (or not taken any interest) previously. He still didn't know much about this worship gig, but attempted a quick silent plea to Tyr for strength in battle should they meet such in the cemetery.