Need advice: Best way to activate my unlocked iPhone X

I want to end out with an unlocked iPhone X. One that I can immediately switch from ATT to Verizon , or ATT to another country's SIM card.

Here's my situation:

1) My iPhone X is ready for pickup from Best Buy tomorrow (Tuesday, Nov 7). YAY !!!
I'm paying full price, not on a plan for their Qualcomm modem version that works with both Verizon and ATT).

I'm on ATT but want CDMA support since I might move to a location that much better Verizon vs ATT support.
Plus, I learned the hard way (during a business trip to Dubai) that my iPhone 6+ wasn't really unlocked, even though I went through the ATT unlock process.. So I had to buy a new phone there on the spot in the Dubai airport and wasted precious hours before a big presentation.


2) After reading the post by Alef_Meem on this thread on Best Buy forums
http://forums.bestbuy.com/t5/Android-iOS-Mobile-Phones/Factory-unlocked-iPhone-X/td-p/1079351
I ordered a Verizon / Straight Talk SIM Activation Kit from eBay.

However, it does not arrive till Saturday-ish.

The key seems to be, *before* I put in my ATT sim, I must put in a Verizon sim.
“. If you fail to do this and insert your AT&T SIM for initial activation, the phone will lock to that carrier’s unlock policy”


Here's what I see as the possibilities. What do you think of Option B and E:

Option A: Wait for the Verizon / Straight Talk SIM I ordered to arrive.
(but I can't wait! That means I couldn't use my new iPhone X till the weekend!)

Option B: After picking the iPhone X up from Best Buy, I'll go to a Verizon Store that's < 5 min away.
I"ll ask the Verizon sales person if I could use a SIM card to activate my new iPhone to Verizon in the store since I might get a Verizon plan if I move.

Option C: Go to Walmart. Buy a $49 Straight Talk Wireless card.
(Nope. Too much. I'd consider this only if the minutes didn't expire. But I only have 30 days to use the minutes.)

Option D: Activate with my ATT SIM. Then go through the ick ATT unlock process. Even if it works, it would take a lot more time than if I just quickly put in a Verizon sim.
(If nothing else works, I guess I have to do this…)

Option E: Find a SIM card that I’ve used on work trips to France (via SFR), Germany (via O2 maybe), or the UK (via Orange).

Does the SIM have to be Verizon to accomplish the purpose of starting out life with an unlocked phone?

I might also have an old T-Mobile SIM somewhere...

 

fyi - This is the Sim card i bought on eBay. It was mailed Monday, so I probably won't get it till Friday.



and this is my second iPhone X which hopefully will support Verizon too.



Question:
How will I know I've fully "activated" it with the Verizon SIM and it's now OK to replace with my ATT SIM?

 

SUCCESS !! I used a variation on Option B.

The Best Buy Mobile Advisor kindly took a Verizon SIM from a demo phone, put it into my freshly unwrapped Best Buy iPhone X, and took it through to activation.
He then restored to factory settings.

At home I then installed my ATT SIM from my iPhone 7+. Shazam! Connected to ATT right away.
Restore from my old iPhone backup was fairly smooth.**

Best Buy Mobile Advisor did warn me that my phone could lock to Verizon once he activated using the demo Verizon SIM card. That did give me pause. I simply told him he'd have a crying female on his hands if that happened .

The Verizon store associate would not help. They said they inventory all their SIMs and they are $19.95.

If I ever switch to Verizon, I'll go back to that Best Buy store to sign up with them.


** 2 things I always forget when restoring from iTunes backup
1) that my encrypted iPhone backup password is different from my Apple ID password
2) to turn OFF "Find my Phone" on the old phone BEFORE attempting a restore.