Yes, clicking a button to generate new conclusion events according to user settings is a good idea. Step 1: enter the transcription and then step 2: generate or regenerate objects.
In Gedcom 7.0 it is now possible to have an ASSO tag under an event. This is how they model multiple participants for an event. There is a ROLE tag under the ASSO tag.
There are some roles that we are missing. They now have Father, Mother, Parent, Child, Friend, Neighbour, Officiator and Multiple (for multiple births). We should probably add these to our event role types. I also note that Bride and Groom have now become Wife and Husband. Should we change these? Do we want to add any more standard types?
You need to be aware that if a participant of an event has a role other than Primary or Family, they will not show up in all reports. Are you planning to use the event role type for the relation to head of household column? If so, we will need to consider how to handle this issue.
As far as the persona concept is concerned, I think that it is a good idea. However, it will need changes to our data model, so you probably don’t want to include this in your initial contribution. If you are interested in developing this feature in the future, then let me know.