Migrating data from old Mac to new Mac

Yes that work if you have the iMac model with an Ethernet port built into the power brick or use a USB-C to Ethernet adapter.

However keep in mind that it will be much slower than Migrating from your 2012 iMac's Time Machine backup.

see > Transfer to a new Mac with Migration Assistant - Apple Support

Yes, that may work. However the most reliable method is below:

Thanks very helpful and exactly what I needed to know

Your welcome.