Thanks again Paul2009! Understand. GoDaddy's method is so much more complicated (and more chance of error) than just following the standard connecting of a third-party domain name according to Squarespace, manually. With all my research I just now stumbled on this from Squarespace support: To keep using your current email provider, you can connect a third-party domain to Squarespace without disrupting your email service. Connecting your domain to Squarespace only involves changes to CNAME and A records, so if your domain provider also hosts your email, there’s no need to adjust your nameservers or MX records.
It sounds to me I can continue as usual and follow your suggestion and ignore GoDaddy's.