"The thing is, can i order SIM card from amazon, such as https://www.amazon.com/eGift-Promotion-Tracfone-Phone-Prepaid/dp/B0728N8PT9."

Specifically, you cannot use that SIM if your goal is to unlock the phone. The phones you bought came with SIM cards, and they must use the original SIM cards to qualify for unlocking. (Tracfone actually tracks use for the unlocking requirement by the original SIM card.) If for some reason the original SIM cards are not available, Customer Service might be able to pair the IMEI with a replacement SIM card.

My guess is that phone will have to contact an eligible tower to actually activate. The process online indicates that the first phone call is required. From Tracfone's Terms of Service:

"Tracfone Service can only be activated where Tracfone Service is offered and supported by Tracfone. " and "You will not be able to make or receive calls on your Tracfone when you
are located outside of the United States, Puerto Rico or the U.S. Virgin
Islands."