I am going to my MIL's funeral next week. Households can travel to the funeral together in a car as I understand. At the church we have to stay in our households and a seating plan has been prepared so we are all socially distanced from other households/bubbles or individuals attending. The church can fortunately accommodate 30 people which is the maximum anyway and there isn't going to be any social event afterwards, we'll save that for the summer and hopefully better times. We all have to wear masks, no contact or hugging outside of your household group/bubble. During the service there will be recorded music only, no singing. To answer the last part of your question nailit adult children with their own children must stay in their own family group/bubble and not sit with their adult siblings and their families - that's what we have to do next week.