Originally Posted by
BusinessOnly
... is it likely between now and October 2022 some aircrafts will change ...
October 2022 might as well be a century away. Anything - literally anything - could yet change with these bookings and plans.
But yes: sometimes 4-class aircraft are operated on 3-class routes. See
https://www.flyertalk.com/forum/brit...-aircraft.html - but don't count on this being the case on your flight, when it actually comes time for it.