Phone has died and we need a new one fast
As long as you buy the USA version of the Moto G5 plus and you can live with Tmobile’s coverage, then go ahead and buy the phone and SIM from Amazon. If you need Sprint coverage, then I believe you still have to buy the phone from Republic’s store.
Your contact list, photos and calendar if backed up on Google should transfer as soon as you enter your Google account information. It’s my understanding that messages will be an issue, since you need an app on the broken phone to transfer the messages.