Recently I setup Facetime on our home iPad 7. Of course it didn’t work at first. After searching the forums, I changed the specific profile “Block literal IP addresses” setting from checked to not checked. This made facetime work. But not being one to leave things alone, I went to Apple support (https://support.apple.com/en-us/HT202078), learned of all the ports Facetime uses, and setup an all day / all week Calendar that I thought would provide access. After checking that Facetime worked, I again checked “Block literal IP addresses” thinking the Calendar will allow Facetime while all other literal IP addresses would be blocked. Facetime did not work. It only works when “Block literal IP addresses” is not checked.
So I surmise blocking literal IP addresses is higher priority than a Calendar which is why the Calendar does not enable Facetime. However, I thought I might check with you to know what’s going on for sure.
Running Newwifi-D2 v2.4.5 with only “Enforce Access Control” checked and Cleanbrowing family filter. No Black or White list entries.