Damn, a lot to answer.
I liked your strategy, at last, But the Wizard died.
1)
"You don't know Mind Blank. Have you swapped out Power Word Stun? Let's assume you have."
It's Wished Mind Blank.
Wait, who Wished it? The Sorcerer? So, the Sorcerer is daily down their 8th and 9th level spells. Cool, Wizard waits until the Celestials despawn, waits for you to recast them, then hits, because you don't have Mind Blank up.
The Wizard is dictating the timing, here.
2) "So, here you have a problem, your Sim can't cast the 9th level spell. I guess you can use the 8th level spell slot, but now your Sim can't upcast level 8 Aid or use Mind Blank on you. This means that, on any given day, you can either have Aid up (cast yourself) or Mind Blank. Which have you chosen?"
Level 9 Wished Mind Blank
Level 8, Aid upcasted
3) "That isn't a sorcerer, right, because any sorcerer with twin can do this as well. But, zombies aren't even really cannon fodder at this level, so this isn't much of anything. They don't fly, so they're not part of your camouflage."
Well, they can shoot arrows and destroy structures.
Which we don't care about.
4)" Now, the wizard is smart, so when he sees all of the Seeminged minions, he puts two and two together and knows this gimmick. He also knows that only you are mind blanked (or finds out through more targeted scrying attempts). He also figures that the two with bows are probably not you, and neither is the one on the flying horse, because he can scry that one. I suppose you could move the Mind Blank around, but the wizard is pretty smart and also tries to scry you every day as well as the others. He can spend lots of slots on this effort, daily, and does. Also, he's smarter than you, so he figures it out eventually, identifying the main components of your entourage and getting a feel for a usual routine (the few hours of speech-making, some of the spell casting that take awhile, etc.) He actually hopes you start going all subtle spell on him to hide your casting because that tells him you're a) a sorcerer and b) are burning up sorcery points! Both are good."
Well, the only one you saw casting was MMD Simulacrum, so you know she’s the cast.
Fortunately, The Simulacrum and Sorcerer regain Sorcery Points with each short Rest for subtle spell a lot.
Um, no, you regain Sorcery Points on a long rest, not a short one. You have to sleep. And the Sim can't just burn slots for points -- they'll run out real fast and you can't really afford to be using your wish to replace Sims.
MMD is continually using the guidance spell.
Even the most intelligent Wizard was deceived.
The only spellcaster for you is the MMD.
Also, Inside the fortress, Scrying is blocked.
Mighty Fortress doesn't block scrying.
5) ALTERNATIVE: The Scrying spell says you see and hear "as if you are there." This indicates that the Wizard can cast True Seeing, then scry, and immediately pierce the veil and ID all the Seeminged minions except the Master. This reveals a lot, even with the Disguise kit (the skill cannot cover the difference in creatures you have going -- it's not magic).
For you, all creatures has a Magen Appareance.
Disguise Kit, Seeming (True Seeming is counter by Mind Blank), Deception +17, Actor feat, Magical Guidance and Guidance cantrip +1d4.
Certainly, It foils the wizard.
No, they don't, because that's not how Disguise works. The Magen don't have wings, for one, which you can't Disguise kit into not noticing. Secondly, the celestials are large, so disguising them doesn't work. So, you can maybe make the DMM sim, you sim, and you look the same, but the DMM doesn't have wings either. Since you're flying, this is critical -- I can ID you and your sim from the rest of the minions reliably.
And, that's even easier, because you're mind blanked and the sim isn't, so if I can scry one, it's not you -- you're the other one that look exactly alike.
Disguise is handy, but you were leaning heavily on the Seeming to paper over these problems in appearance that can't be covered by disguises.
6) "Teleport to location viewable in scry, about 1/2 mile away, gaining Surprise. Simulacrum casts meteor swarm on the group. Wizard promptly casts Meteor Swarm on the group. 240 average damage, assuming you make no saves (being generous, DC is 21, your Dex save is +2, so is your Sim's, and the celestials, the DMM is +4). Your simulacrum is destroyed. Any Magen in your Seeming range are destroyed. Both Celestials are destroyed. The DMM is destroyed. You're probably fine, with the lower than 8th level Aid up (I guess you could use your 7th level slot?). Then, you counterstrike, killing the wizard."
The Wizard did 0 damage.
Here's your biggest mistake. Meteor Swarm hits the ground, Flying creatures are immune to Meteor Swarm. The Wizard wasted a 9th spell slot and 7th for nothing.
Ah, you're never within 40' of the ground -- good to know. And all of that nonesense about Mighty Fortress is pointless, because you're never on the ground! Also, I guess you sleep and eat and poop while flying above 40' at all times? Yeah, no long rests for you!
As for the spell, there's a bit of interpretation there that you're bending heavily in your direction, like you do.
Again, the wizard has the initiative here, so the encounter takes place when it's optimal for the wizard.
7) "The Wizard's Clone wakes up........ You now have no Magen, but are down HP from them. You're down your bound Celestials. You're down your Simulacrum. You're down your DMM Sim. The wizard is down 2 5th level slots and a 9th (scry, teleport, meteor swarm). You're down a lot of HP -- if you had a 7th level Aid up, you had 125+30 and 24 temp hp. The first meteor swarms kills your sim -- they take 120 and half of your damage, which blows through there half-hp+24 temp. You take half of this, for 60 damage. The second one is all you. Total 180 damage. You have 179 hp. Let's say the dice roll low and you lived. The wizard can teleport unerringly to his body (he has a piece of it) and anything at this point kills you."
Well, the Wizard's attack failed, dealt 0 damage and is exposed to Sorcerer's attacks.
Yeah, you covered that and are now just repeating yourself. The Wizard picked a better time.
Power Word Stun + Disintegrate spell, prevent you from returning to the Clone spell.
You don't have an 8th level slot to PWS.
8)
"Notice that none of this requires Wish, or Divine Intervention. Just lots of grunt work with daily Scrys until enough information is found to initiate the alpha strike -- the wizard doesn't really care about surviving this. If he doesn't get you the first time with this -- let's say that you're luckily not in the area and they made a mistake in IDing you, they'll still wipe your minions (they're going to target to maximize that damage, and your minions have to be pretty close to you). So, what? They caused immense damage to your defenses -- you cannot raise more Magen because you can't afford the hp loss. You'll have to restart the Wish chain to get back to having Simulacrums and/or summoned Celestials. You'll need to go get another Drow Matron Mother to Sim -- how did you do that, by the way, especially without being hunted by powerful drow? It's a downhill spiral now. The Wizard can Sim up in 24 hours, and be back with a similar plan, but unlikely to miss you this time -- and now you don't have Aid or Warding Bond! The second pass with be the Sim opening with Dispel Magic at 9th level and then a meteor swarm from the Wizard, or power word stun. Or, to follow up the Abjurer bit, they encase you in a Prismatic Wall, and then pop in and snipe while you're blinded.
EDIT: whoops! I messed up with your hp -- I gave you both an 8th level Aid and then a 7th level one! You don't have the hp to survive the meteor swarm alpha strike!"
Well, it seems that the strategy did not work. But thanks ! It was creative and much better than "I wish, DM help me".
Oh, it worked, because I was able to accurately identify you, and then time the strike when it would work best. Alternatively, I could have just popped in, dispelled you at 9th level, and then cast Power Word Stun on you -- you have fewer that 150 hp now. That incapacitates you, which disables your wings, and you're pretty high up, right?
One more thing -- the Summoned and Bound Celestials? They're not loyal. They have to follow your commands, but they'll try to twist them. This is because they're good, and you're pretty evil, what with the Finger of Death army, so they're not friends. Your minions aren't perfectly loyal! Haha, and I haven't even brought my actually loyal minions in yet!