Regardless of the risk or a delay on the inbound, this looks a tight connection - presumably the EZY flight is from the North Terminal, so you’d have to clear immigration then transfer to the other terminal. If you’re checking bags, that would seem impossible.

The Vueling option means you’d stay in the South Terminal but you are unlikely to be able to add that to a BA booking (unless there is reward availability on a codeshare), so you’d still have many of the same issues especially with checked bags.