and less expensive . We will not see the wifes/husbands of the Members of the House of Lords and Commun.
I doubt we will even see all members of either House - but those that do attend will have their partners I am sure.
Outside the royal family and Camilla's family I imagine:
GGs and PMs of the other realms, with partners
Presidents or representative from other Commonwealth nations, with partners
High Commissioners from all Commonwealth nations, with partners
The Cabinet and partners, PM, Opposition leader and First Minister and Opposition leader and partner from the devolved nations as well as all living ex-PMs and partners
Knights of the Garter and Thistle and partners
All living VC and GC recipients and partner (they attended the late Queen's funeral for instance) from around the world
The senior peer in each degree plus any other peers who, traditionally, have a role to play unless a senior peer in their degree e.g. Duke of Norfolk is the senior Duke and Earl Marshal
Both Archbishops and the Bishops of the CoE
Representatives of the other major religions represented in the UK and Commonwealth, including other Christian denominations
Some foreign royals, with partners, but largely extended family.
Representatives from allied nations - possibly just the Ambassador and partner
Lots of representatives from the organisations and charities with close ties to Charles and Camilla
I really can't see say Crown Prince Frederick attending and not Crown Princess Mary or the PM and not his wife
I don't think any of the peers, other than the most senior peer in each degree and those with a part to play based on tradition and hereditary right, being invited ... and only if the homage remains in the ceremony, which I am not sure will happen. If no homage than only those peers with a role to play will be invited.
I am not convinced he will have all of the BRF present. He has two royal dukes about whom the public have issues and the easiest way to avoid any issues with them is for it to be 'working royals' only plus maybe George and Charlotte but no Beatrice or Eugenie, Louise or James, Peter or Zara. Charles may want them there but it would be hard to have them and not then invited Harry and Andrew and as much as he may love them as a father and brother the British public hate them with a passion and their presence would be a distraction - look at the way Andrew was pilloried for daring to go to his father's memorial service or Harry and Meghan at his grandmother's Jubilee. Easier to penalise the non-working royals and then avoid the headlines about either of the other two and the public would accept 'working royals' only as that would also free up seats for others.