+4 is actually 50/50 at DC15, but it's a save so Wizard gets proficiency making it +9. As a save, it can further be enhanced by Bless (if it were an ability check, one would of course use Enhance Ability instead). Each COP only takes 11 minutes to cast so this is actually doable in the time Planar Binding is done by the others (5 questions each meaning 44 minutes to ask 20 questions). At double speed with the Simulacrum and the Wizard.
Like I said, I posted the saves in the roll thread. 15 on the first one (with reroll and Bless available depending on DM ruling on Bless) and 22 on the other two so all 3 pass without using Lucky, even.
I posted the buffs. Most of those prep spells have been cast long ago I'd assume: there's no reason not to have a familiar if you're a Wizard. All it takes is 1 hour 10 mins and 10 gold. Same with most of the other stuff: really, stuff that's specifically cast for this fight is only COPs/Communes and then Heroes' Feast.
My total buff loadout is:
- Inspiring Leader speech from the Druid
- Longstrider/Darkvision/Mage Armor on basically everyone who would benefit (turns out to be surprisingly many in this party)
- Aid, Heroes' Feast on everyone
- Death Ward on Simulacrums & the Bard
- Freedom of Movement on the Bards
- Fire Shield on Wizard and Simulacrum
- Contingency on the 4 who can use it (Bard & Simulacrum, Wizard & Simulacrum, slots marked off for it for the Simulacrums since they need to recast it after creation)
- Phantom Steed on all the 6 casters (the Wizard & Simulacrum both maintain 3: this takes half their uptime)
- Rary's Telepathic Bond on all the 6 casters & Couatl and Giant Ape (Familiars don't qualify due to too low an Int but they're naturally telepathic with their masters anyways - alternating casting between the Wizard and their Simulacrum to keep constantly active)
- Programmed Illusion on the Bards' Longbows to create a cloud of darkness on a command word (basically used to gain Unseen Attacker bonuses at range)
Phew, I think that's everything. Oh and due to foreknowledge of an extremely powerful entity, Bard has cast Elemental Weapon VII on Thunder (as always). There may be some errors in the statblock as editing a bunch of them so fast is a pain but I tried to be consistent and precise.
EDIT: While it doesn't matter in this case, to be conscientious and play like I'd normally play with a party like this, I'll say the Simulacrum uses a 3 on Tiamat's Initiative making Tiamat's Initiative roll a 3 instead.
EDIT#2: Oh yeah, and the Wizard actually has the Bard Simulacrum while the Bard has the Wizard Simulacrum. So the Bardluracrum acts on the Wizard's turn and the Wizardluracrum acts on the Bard's turn.
EDIT#3: And the Simulacrum has a bat, not an Owl familiar.
EDIT#4: Should we make another thread for the fight? This could be the OOC thread in case other people wanna try different parties out too. Though I think an enclosed space like the Great Apse would make for a better fighting arena (because it would keep kiting viable but no longer an autowin and OTOH Timmy would be restricted in terms of mobility too - a featureless plains is almost never a realistic environment, though of course a simple one).