Will this work with Verizon network and total by Verizon?

Unfortunately it will not.

If I buy this phone, check that its IMEI (outside the packaging) is incompatible with the network provider, can I return & exchange for another phone rather than getting a refund & pay the difference if the other phone happens to cost more? Thank you.

Yes of course and we'll pay for the return shipping costs. 

However, we cannot process exchanges/replacements. We would need to issue you a refund for the initial order then process a second separate order.

Will this work with an MVNO within the United States?

Yes it will but it won't work with AT&T or AT&T's MVNOs

Will this work with an MVNO that piggyback's off of T-mobile's network? Does this have NFC?

Yes it will work with T-Mobile's MVNOs. Yes, it has NFC

Will this work with T-Mobile in the US and Telcel in Mexico? Also the NFC work with digital payments?

Yes it will work with T-Mobile in the US and Telcel in Mexico. I'm not sure about NFC

Does this phone support both Dual-SIM and eSIM?

Yes sir and just so you know, it's a Nano SIM card