While I would like most of the stuff on that list they’re mostly new feature requests not parity issues per say…
I can only count a few of parity things… My opinion of course 
- IFTTT for JA’s - 103 votes
- Overdrafts for Joint Accounts - 99 votes
- Different colour card for Joint Accounts - 89 votes
- Split the bill with a Joint Account - 26 votes
- monzo.me for Joint Accounts - 25 votes
- Schedule a regular payment to Joint Account - 19 votes
- Notifications for own card with Joint Account - 16 votes
- Make the Joint Account the main account - 15 votes
- See friends Joint Accounts - 12 votes
- Joint Account cards concept - 12 votes
- Multiple Joint Accounts - 11 votes