You can always try installing Norton. If there are no issues, then you would not have to use the removal tool for McAfee.
But then again, how do you know if there is something in the background that is not working correctly? It cannot hurt to run the McAfee tool, then reinstall Norton if you had already installed it.
As far as removing a trial of mcafee which came with the laptop - the mcafee was not started. The wife deleted the mcafee program and it seems to indicate it was uninstalled. In that case do you still need to use the mcafee removal tool? The mcafee site says to only use the removal tool if the program did not u install
1. Norton's installation process will take care of disabling the Windows Defender features, including the firewall.
2. You can just use all default settings for your new install. That will give you the needed protection. If you want, you can always go through all the settings to see if there is something you might want to disable.
As this is a new computer, be sure you fully remove any non Norton trial security products that might be on your new system using the removal utility for that software before installing Norton.