Congrats on the new baby!

There is NO reason to do a clean OS X install. It's not like Windows, there is no bloatware, there is nothing... It arrives out of the box the exact same as it would be if you reinstalled OS X. Would just waste 30min - hour of your life

Norton is probably the worst possible antivirus for PC's, and Macs are not susceptible to virus' or malware like Windows PC's. When a virus comes to OS X, it will be ALL over the tech world news. And Apple would fix it in a heartbeat. There's really no need to waste resources or time with that either

Just enjoy your new machine! Best to go into it not thinking of Windows at all, the two are designed/used in
entirely different ways!