Unfortunately I do not block Nintendo connections because I do not use any Internet services. I simply deleted all of my Wi-Fi settings and do everything offline.
I recommend following this guide
instead. No, you do not have to restore your sysMMC before setting up emuMMC. In fact, if you restore it before setting it up, it'll be counteractive towards your goal. When you setup emuMMC, it starts off as a copy of your current sysMMC so if you restore your sysMMC backup now, your emuMMC will become your sysMMC backup.