Can I just tell Tom to switch my Sprint LG G3 phone from Sprint to Verizon since they are both CDMA?
Possibly when CN starts offering service on other carriers, but it's going to be more complicated than that. Your LG G3 would have to be domestically unlocked, you would have to get a Verizon sim card and you may only get g3 service. Other carriers use different frequency bands. I am currently using an unlocked sprint note 4 on ATT with redpocket and I only get 3g. Your LG G3 would probably work on T mobile also. Do a lot of google research first, thats what I did. I'm not at all familiar with your LG G3 so maybe someone who owns one can give you more information.
Most sprint phones won't work on verizon.
After all my research I still wasn't sure if I could use Verizon. ATT works fine though. ATTs g3 seems about as fast as Sprints LTE.
Unlike Sprint, Verizon doesn't use whitelist. So I believe most sprint phones work with Verizon at least 2g/3g.
Actually I put activated xm(Verizon) sim into my Chinese phone, it works flawlessly. I use that dual sim phone for xm(unlimited voice/txt) + fp LTE Sim (600mb data, swap to 2x, 3x...)
What is the xm carrier?
I thought Verizon does whitelist for activation? You can swap a sim that is already activated and it will work on another phone. If they find out though they can block the account - it has happened at least once. Though maybe just an isolated incident.
But many sprint phones are locked tight which is a problem. And don't have band 13 for verizon. Nor bands 2/4.
In any case cellnuvo have not announced the ability to swap to verizon yet. I'm still trying to find out from Tom when and how this can be done. It should be possible now as we are on redpocket and all they need to do is port you over to a verizon sim. But making sure the cellnvuo account links to the new phone/service is necessary. I'm not trying until they give the all clear.
I'm waiting for GSM swap, wonder how long till then.
Can you please share details on your dual SIM Chinese phone? Most of the dual SIM phones don't work with CDMA (Verizon, Sprint), but I've heard some do, like OnePlus 3... I'm trying Xfinity Mobile and I would love to keep it if I can just use it for calls and text, avoiding data charges. Dual SIM phone letting you do this, with the second SIM for data, would be perfect, ...if the phone is not to expensive (?)
If you didn't get your Sprint phone domestically unlocked before leaving Sprint you will have to pay an unlocking service to do it for you. About $35.00, and most likely root your phone first.
Xfinity Mobile, Verizon
I think any "All CHINA carriers " phones sold in China can do that. China Telecom uses CDMA for 2G/3G.
In China such phones with like QualComm 6xx/3GB/32GB are normally under $150, but they lack of US LTE support. If Freedompop LTE working at HSPA speed is enough for you, these are perfect phones for such purpose.
High-end phones like $300 in China may support US LTE. My phone is one of them. See pic
Thank you very much, I appreciate the information 
I tried verizon on a oneplus 3t. The oneplus 3t (and 3) only have one of the [strike]two[/strike] three cdma bands so coverage can be an issue. I had a weak signal at my house though normally it is pretty strong with a proper verizon phone. So I wouldn't get the oneplus 3 for verizon.
It also disabled the second sim when the verizon sim was in. No standby. So basically reduced it to a single sim phone.
What phone are you using min68?
Leeco max2.
The model has x820(Chinese), x821(Indian) and x829(US). Only x820 and x821 work this way. X829 doesn't have CDMA antenna as far as I knew.
Thanks - that one has a pretty comprehensive set of bands there.
I would pay in Gold for it