When a priest is unavailable are there general rules for conducting a service and distributing Holy Communion? eg Who may conduct Read the gospel of the day etc
Yes, there is a rite that can be led by a deacon or a layperson. Here is information from the USCCB; other countries would have their own regulations. usccb.org/prayer-and-worship/the-mass/frequently-asked-questions/weekday-celebrations-in-the-absence-of-a-priest.cfm
Ideally, a deacon but failing that any lay person can do it.
Not sure how correct this is. In my diocese one must be a commissioned Lay Leader of Prayer to do this type of service, and that requires training. One also must be a commissioned EMHC. I know, because I received my commission from the Bishop last year.
It depends on the country and the diocese. I know in mine it wasn’t that formal.
In Canada the Rite says that it’s better to have two people lead the service, one for the Liturgy of the Word and and EMHC for the Communion Rite.
In my parish that means there are usually 5 people involved in a Sunday Celebration of the Word with Communion: the Leader of Prayer, the EMHC and 3 readers. Two of the leaders are also EMHCs, so serve in either role; the other two leaders are also readers.