I expect the same as well. If, and this is a big if, they do come to the Coronation, they will be on a second row for official events and thats it.If they do attend the Coronation, then I hope their invitations to 'after-events'/receptions are limited as was the case at the Jubilee and HMTQ's funeral. Wouldn't put it past them to hustle their fellow invitees for voice-over work. If just the extended family events with overseas royals, then hopefully KC3, QC, W & K & royal cousins would be doing the round of the greetings. Can't see many (if any) wanting to engage with Harold & TW beyond 'lovely/awful weather we're having' or from TW 'it was very colourful'
For the Jubilee, there was a “cousins lunch” I think where they were not attending - I believe they were not invited.